I would say that is exactly what is going on, with the current state of the world economy most likely a heavy contributing factor. While the sales are still there (obviously) it seems to be in a bit of a lull. Rick recently touched on this in one of his posts and I consider him a seer when it comes to this stuff.
ricksblog.com/my_weblog/2011/04/in-1996-what-did-i-set-out-to-create.html
"Lastly, revenue since I am online has now crashed THREE times. In the adult world around 1999. In mainstream in 2003-2004 and as we are all witnessing 2010-2011. But each time the crash occurred, things ROARED back stronger than ever. That's the nature of things and I don't expect it different in the future."