Won't take long...Dreamcast and XBox both dropped pretty quickly - within 6 months if I recall correctly. Consoles that aren't "in first place" can't afford to be tough about their price when the big kid on the block is about to drop a bomb on them.
I could be wrong, but I'd be surprised if it were still the same price, say, 8 months after launch...give or take a few depending on Sony/Nintendo's plans. I guess to some people that may seem like a long time, but I have no problem waiting if it's going to save me 50-100 bucks, especially when I still have in-plastic XBox games I haven't had time to get to yet (and probably won't for quite a while yet).