Sounds like an opportunity for a consortium of like minded photographers to get together and sell their own work on their own stock site... cut out the middle man!
There are a few groups who've done this, I can't think of them off the top of my head so I couldn't tell you how well it went.
Back to the original point, I believe it used to be a much more lucrative market before the internet came along and spoilt the party. One of my uni lecturers used to make his living solely from stock photography (slides not digi) up until the mid-late nineties. Then, the internet rocked up, and both of his main libraries were too slow off the mark with the new tech and were left behind as a result.
He was telling me about one of his mates the other day.. This guy was a serious stock photographer, his main income came from one three week trip each year to the Maldives, he'd take 4 models (2 male, 2 female) and pay for all their flights, accom, expenses whilst there. Shoot 16 hours a day for 21 days, then come home, edit the slides and send them off to his libraries. He was making crazy money from this, even 5 years after he quit, he made $600,000 (Aussie dollars) from stock sales. Not bad for not doing a days work all year.
Some of the top contributors still make a lot of money from stock sites, but I'd imagine its very hard to break into in any serious way these days.
Cheers,
Jamie.