Nvidia has released many demos over the years showing what GPU accelerated PhysX is capable of, so I doubt it's a lack of marketing.
As I said in my previous post, I think the reluctance on the part of game developers to take full advantage of PhysX, is because it's specific to Nvidia hardware..
Once OpenCL becomes available, things should change....or if ATI ever adopts PhysX.
Did you see the Fermi PhysX demos btw? The most impressive one is the
rocket sled, but there are others as well, featuring
hair and
fluid physics.