It never dominated. Of course, neither did the other two consoles. RPGs were much bigger on Handhelds.

I mean look at how poorly recieve all the 360 RPG's have been. The most liked one, Lost Odyssy, dropped in price extremely fast, so not many people picked that one up, or lots were traded back in.

And a lot of people thought very poorly of Star Ocean 4.

Probably the only RPGs to do well are Disgaea 3, and Cross Edge, which seems to be doing well, even if they didn't make that many copies, and in their typical fashion already discontinued production.