From my perspective, a PS3 with no backwards compatibility is worth that much less (the cost of a new PS2) because I need both. And since my 2nd PS2 is becoming restless, it's an easy-but-frustrating choice to just get a 3rd PS2 now (2 years life per console? That's pathetic to me, but at least it's affordable).
I'll never pay more than $150 for a new PS3 with no backwards compatibility, even if it means I never get one. :p $250 with backwards compatibility would be fine though, I don't mind waiting a few years, considering I waited 3 years for the PS2 to drop in price. :) (I have an *extremely* tight budget, either I get hardware or games, not both)
Nobody is crazy enough to accuse me of being sane.