"I also try to avoid these stories as much as possible since I think the coverage is way, way, way, way, way overdone."
I agree, Ken, but there it is. Night after night, the cable channels slobber all over each other to bring us "up to date." Of course, it turns out that there's often nothing to say, but it gets said anyway. (The Holloway case seems to break new ground; once, on O'Reilly, Bill had an Aruban reporter on the video link and asked here what was going on. She, refreshingly, said she didn't know any more than he did.)
I have a couple of suggestions, and they're only that, about the popularity of such coverage: The victims are, in fact, "cute" and appeal to a large segment of the audience. Coverage is pretty cheap, compared to digging up "real" news and can fill hour after hour just on speculation and rehashing. And, apparently viewers like it. Otherwise the networks wouldn't beat it to death for so long.
And they occur disproportionately in the summer, when there's less other stuff to cover. Holloway has been a mainstay this summer for the cable channels; rememember that the Chandra Levy disappearance happened in a similar slow "news" time.
And I suspect that the cases that attract the most attention are raised by the most media savvy folks; Holloway's family has been happy to appear every day, sometimes several times a day, to comment on the least scrap of information.
(The Holloway case also has another lure for reporters: Go to Aruba, report that nothing's happening and enjoy the sun and surf. Would they be so willing to go to Fairbanks in January?)