I don't know, I could be wrong but I suspect that removing backwards compatibility entirely was a very bad move; even having 25% backwards compatibility with the promise of improvements down the road would be much better.
I don't have a perfect picture into people's minds so I don't have a full understanding of their purchasing habits but I do know that backwards compatibility became a huge deal for many consumers after it first started being introduced; the PS2 and Gameboy Advance were bought by a lot of people who were very interested in playing their old games on their new systems.
I really believe that less people would be disapointed if they dropped the ability for the $400 PS3 to play Blu-Ray movies than for it to be unable to play PS2 games.
