“I’ve heard some rumors that the PS4 will not be backward compatible to PS3 and earlier games. Anyone got more concrete information?”
It’s not a rumor ... it’s a fact and was discussed by Sony. Sony moved away from the Cell architecture and went the x86 route. It’s not going to be possible to emulate the Cell via software for a long, long time.
They are supposed to “eventually” support PS3 titles on the PS4 using some kind of streaming technology Sony purchased. The idea here is to run the game remotely on PS3 hardware and stream the video, etc to the console. That’s probably going to be a while as well though ... unless they allow you to install this program on a local PS3. They haven’t released much in the way of details about this though.
So with buying all new games in add., seems like quite an outlay of cash required