It is not the age of the manuscript itself, but the quality and antiquity of the text it contains which is the real item of value.
Professor Robinson puts it this way:
Most early manuscripts in existence today have been affected by the uncontrolled nature of textual transmission which prevailed in their local areas, as well as by the persecutions which came continually against the church. The whole matter of early copying practices is hypothetical, regardless of which textual theory one prefers. We know nothing beyond what can be deduced from what survives. In the early papyri, we may have only personal copies, and not those which were generally used by the churches themselves. Also, the papyri all come from a single geographic area, and reflect a good deal of corruption, both accidental and deliberate. One should not summarily question the integrity of all early manuscripts because of the character of this limited sample from Egypt.
There is good reason to presume that most early copies -- many made directly from the autographs themselves -- would have been as accurate as ordinary care would humanly permit, especially for Holy Writ. Church sources in particular would not knowingly send forth what they would have considered "defective" copies. At least the first and second copying generations should have been generally secure. Responsible scribes would presumably take general care with their sacred deposits.
Although a healthy respect for the sacred text generally prevailed, keeping corruption to a minimum, even the orthodox sometimes took the opportunity to alter the text, under the supposition that they were "improving" or "restoring" the text with their corrections. Heretical tampering did occur, as witnessed by the work of Tatian and Marcion, but the church as a whole, and especially its leaders and theologians, were keen watchdogs against such deliberately-perverted manuscripts. It is not without significance that today we know of Marcion's heretical text only from citations in the Church Fathers, and the heretic Tatian's Diatessaron is seen in but one Greek manuscript fragment, despite its early widespread popularity even among the orthodox.
Yet, even though heretical alterations were not tolerated, nowhere in the early Fathers do we find any indication that in those early centuries a uniformity of text was a concern or demand. Had common scribal alteration been a concern, the Fathers would have spoken out as strongly as they did against the theology and text of the heretics. The evidence of the existing early manuscripts as well as the Patristic quotations of Scripture is plain in this regard. The manuscript text in the earliest centuries had been corrupted to a degree, chiefly through the agency of common orthodox Christians. The Fathers, like all other Christians, had to make do with the manuscripts currently available. They did not actively seek to "restore" the autograph form of that text; such was not their purpose.
The text found in the manuscripts of the second and third centuries, therefore, is in many cases corrupt, and to that extent somewhat removed from the autograph text. Not all manuscripts showed the same degree of corruption, however, as even the early papyri demonstrate.[32] Only the continual process of manuscript comparison and cross-correction as practiced throughout the centuries would succeed in weeding out early scribal corruption and conflicting variant readings. The same process would later keep the vagaries of individual Byzantine-era scribes in check.
With the increased cross-cultural communication which followed the legitimization of Christianity, such a practice would slowly but naturally purge manuscripts from both the conspicuous and even the less-obvious corruptions to which they earlier had been subjected, and a truly "older" and purer text would result. This "process" could not be successful were the basic text of all Greek manuscripts not in large measure "secure." A mish-mash of conflicting readings, such as prevailed in the Old Latin tradition, would never allow for the restoration of an older or purer Textform by a natural "process."
In light of the general uniformity of the Greek text as found in the later Byzantine-era manuscripts, it therefore appears more rather than less likely that these later manuscripts would preserve a form of text closely approximating the autograph. Certainly this would be far more likely than the chances for the autograph readings to survive only in a conflicting handful of second- and third-century manuscripts which were copied under less-than-favorable uncontrolled conditions.
Even more to the point, later manuscripts may often preserve an "early" text. This was one of the main considerations of Hort's genealogical hypothesis. A manuscript of the twelfth century may have been copied directly from a manuscript of the third century. There is no way of knowing this directly, except where a scribe makes mention of such a fact in a colophon (closing written comment).[33] Most colophons, however, do not address the issue of the type of manuscript (papyrus, uncial, or minuscule) from which they were copied, but only those items of pressing concern to the scribe, many of which are insignificant to us, being devotional in nature (we should dearly love to have even the date when each manuscript was copied, but most scribes did not consider that to be of major importance).
We do know that, after the 9th century, almost all manuscripts ceased to be copied in the uncial style (capital-letters), and were systematically replaced by the "modern" minuscule style (cursive-letters) which then predominated until the invention of printing This "copying revolution" resulted in the destruction of hundreds of previously-existing uncial manuscripts once their faithful counterpart had been produced in minuscule script. Many truly ancient uncials may have vanished within a century due to this change in the handwriting style. Those palimpsest[34] manuscripts which survive provide mute testimony to the fate of many of those ancient uncials, the remnants of which, having been erased and re-used to copy sermons or liturgical texts, might simply have perished or been discarded once those texts were no longer considered valuable.
Since Kirsopp Lake found only genealogically-unrelated manuscripts at Sinai, Patmos, and Jerusalem, he concluded that it was "hard to resist the conclusion that the scribes usually destroyed their exemplars."[35] If strictly applied to all copying generations, this view would lead to a number of logical fallacies. Some of these have been discussed by Donald A. Carson and Wilbur Pickering.[36]
However, the real explanation of Lake's comment revolves around the "copying revolution": scribes apparently destroyed uncial exemplars as they converted the Greek text into the then-standard minuscule format. Thus, the apparently unrelated mass of later minuscules may in fact stem from long-lost uncial sources far older than the date of the minuscules containing them. This in itself adds a significant weight to the testimony of the minuscule mass, especially those copied in the ninth and tenth centuries, at the height of the copying revolution.
For modern researchers summarily to neglect the text of the minuscules because they mostly reflect a Byzantine type of text is to suggest that their text is all one and all late, in accord with Hort's thesis concerning the ultimate origin of the Byzantine Textform. Yet Von Soden and subsequent researchers have clearly shown the internal diversity found among the manuscripts of the Byzantine Textform -- a diversity which cannot be accounted for genealogically. An unprejudiced consideration of the present hypothesis will impart a value to (at least) the earlier minuscule testimony which ranges far beyond that allowed by modern critics. This factor now makes the complete collation of all known minuscule manuscripts an important task which should be completed as rapidly as possible.[37]
32 See Colwell, "Scribal Habits," where he compares the relative accuracy of the scribes of P45, P66, and P75.
33 The post-Apostolic document, The Martyrdom of Polycarp, has a colophon which states it was first copied by Gaius from the writings of Irenaeus. It was then copied in Corinth by one Socrates, and later by one Pionius, who had diligently sought out this document and "gathered it together when it was almost worn out by age" (Martyrdom 22 2). This is a clear case of a "new" copy reflecting a text which was already quite old.
34 From the Greek, "to rub again." The term denotes a manuscript from which the original text was erased and a second, differing text placed on top of the original writing. Through the use of various methods (e.g., ultraviolet light), the original text can often be recovered with extreme accuracy.
35 Lake, Blake, and New, "Caesarean Text of Mark," p.349.
36 Donald A. Carson, The King James Version Debate: A Plea for Realism (Grand Rapids: Baker, 1979), pp. 47-48, note 5. Pickering offered a clarification and rebuttal of Carson's critique which differs at points from the present hypothesis; see Pickering, Identity, pp. 230-231, note 30
37 See further W. J. Elliott, "The Need for an Accurate and Complete Collation of all known Greek NT Manuscripts with their Individual Variants noted in pleno," in J. K Elliott, ed., Studies in New Testament Language and Text [G. D. Kilpatrick Festschrift] (Leiden: E. J. Brill, 1976), pp. 137-143.
THE NEW TESTAMENT IN THE ORIGINAL GREEK ACCORDING TO THE BYZANTINE / MAJORITY TEXTFORM
THE TEXT REVISED BY MAURICE A. ROBINSON AND WILLIAM G. PIERPONT
INTRODUCTION AND APPENDIX BY THE EDITORS
EXECUTIVE EDITOR WILLIAM DAVID MCBRAYER
THE ORIGINAL WORD PUBLISHERS ATLANTA 1991
add that we all know that the Elzevir brothers edition came out in 1633 but 1516 gives them the benefit of the doubt even though there were umpteen revisions since Erasmus' first edition.