It's not all that surprising. It takes a while for the RPG devs to really embrace a new platform. For example, Nippon Ichi has only recently announced Disgaea 3 for the PS3, and they've been content with producing more games for the PS2. Same goes for Atlus and a few others.
There wasn't an RPG worth buying during the first year of the PS2's reign, either; FF X was the first must-have, and that didn't arrive until December 2001, 14 months after the PS2 launched in October 2000. Before FF X, all we really had was stuff like Summoner, Okage, and I think a Harvest Moon. The PS3 does have Enchanted Arms, which isn't a bad RPG, so that's one option. Other than that, you'll have to wait until 2008. White Knight Story, Disgaea 3, The Last Remnant, and more are on the way.
