Use of scripture is nice. I'm glad you know scripture. However, its the use and context of scripture that I have a problem with here. This is your statement.
The context of Luke 11:17 is that Jesus was being accused of being the head devil when he healed. It has nothing to do with the early writings of the gnostics. However, supposing your right satan preserved his works are you saying God can't preserve his works? Just because you quoted a text that had to do with the character of Jesus doesn't mean that you've made a point that landmark baptist works were entirely obliterated. That would question the ability of God over satan. The truth is that no matter where or who you are you leave a mark in the world that is discoverable. If its not discoverable it never existed.
God does preserve his works, just not in the way that you want him to.
This is true of many different areas. I believe it is true in textual criticism also: that oldest is not always the best MSS, just because it is closest to the "source." It may well be the closest because it wasn't used and left on the shelf so to speak, preserved with all its errors.
Speaking of the "power of God" and what he could have done, Jesus rebuked Peter for drawing his sword and cutting of the servant of the high priest's ear. After restoring it he told Peter to put up his sword and said to him: Don't you know I could have called 12 legions of angels from my Heavenly Father. 12 legions of angels is 72,000; one legion being 6,000. What can just one angel do?
2 Kings 19:35 And it came to pass that night, that the angel of the LORD went out, and smote in the camp of the Assyrians an
hundred fourscore and five thousand: and when they arose early in the morning, behold, they were all dead corpses.
--One angel killed 185,000 men. What would 72,000 angels be capable of doing?
The point is, that God is capable of doing whatever he deems necessary.
But he doesn't have to do things your way or the way you think things should be done. It seems to us that the enemy often wins. David thought the same thing:
Psalms 73:2-4 But as for me, my feet were almost gone; my steps had well nigh slipped.
For I was envious at the foolish, when I saw the prosperity of the wicked. For there are no bands in their death: but their strength is firm.
The wicked prosper. The poor man, the righteous man fails. He is persecuted. See the patience of Job. God allows it to be so. Biblical Christianity has always been in the minority.
"Yea all who live Godly in Christ Jesus shall suffer persecution."
That is a promise.
God allows it to be so, that we might be conformed to the image of his son. While we are being persecuted the enemy writes books often accusing us of false doctrine. I don't believe that this is far off the mark.