I think it'll be a long time before paysites die off, if they ever do. I think a good program needs a variety of things to appeal to the largest group of surfers. Some surfers aren't happy with one site, they like the 50,000 site appeal of AVS; others like PPV; some surfers see PPV as a waste of money as they don't get to keep anything, so they'll prefer the video download model; and some surfers are always going to be happy with checking in with their favourite paysite a couple of times a week.

I do see a few more companies following the Take My Cum model where the surfer buys a video clip and it's theirs to keep. But you need exclusive content for that model.

Cheers
Michael