I would agree, you've got to think there are more than a few fans of JLA. Looking at recent auctions, the prices have been pretty inflated on high grade issues in the #100-200 range. They had a large number of mile highs up for auction at comiclink and they all went for more than I thought they would.
Granted they were 9.8's, but still...
That must show that there is demand for the issues.
Personally, I just got back into comic collecting a few months back. I had bought a copy of the Overstreet Guide just to see some values and it got me to thinking about my collection. I decided to send a number of comics off to CGC for certification and decided that I wanted to go after JLA's solely.
I've got a long way to go if I want to get all of the original series, but I'll chip away at it as items appear on the internet.
Brad.