So what do you want? What is your solution? Should Sony have kept the Cell and made programming a more expensive chore that requires more frustration and development time on ports? Should it raise the price, size, and overhead of the PS4 by including PS3 hardware? What, exactly, do you think they should do?
Let's be honest. Far, far more people will care about a lower price than backwards comparability. Statistically, the amount of people who play old games on new systems is minuscule. I kept my PS2 plugged up but I've probably used it a handful of times since I got a PS3, despite what I thought would happen.
This is really only an issue for people who don't have a PS3 but Sony really had very little choice here. They did the right thing.