The original 60GB PlayStation 3, which launched back in 2006, was fully backwards compatible; i.e., it would run most all PS1 and PS2 games. It was the last model to be able to do so, as over time, Sony moved to partial compatibility for PS2 titles and eventually, removed the feature entirely.
As of now, no PS3 can play PS2 games (although they can all still play PS1 games). Sony has remained firm on the matter, saying almost from the start that over time, backwards compatibility will be less and less desired by fans. While they may be right about that, the fact remains that many PS3 owners wouldn't mind being able to play PS2 titles on their new system. This is why Japanese message boards have exploded overnight due to a recent patent filed by Sony Computer Entertainment Japan. As you can see, it appears to be an external adapter of some kind, that connects a new generation console to a previous generation console. A schematic for the intriguing device shows that it "has its own processor, a DVD decoder/emulator, sound processor, and graphic processor." This could be very big news for the PlayStation family…and has anyone thought about the idea that it might be an adapter for the PS4? So we can play our PS3 games on the new machine?
Don't forget we'll be entering the fifth year of the PS3's lifespan in 2011 and the last two gaps for PlayStations were five and six years respectively- 1995-2000 for the PS1; 2000-2006 for the PS2. True, they say the PS3 has a 10-year life cycle but that doesn't mean they'll stop selling PS3s when they launch the PS4; the PS2 went strong for three full years after the PS3 arrived, giving it a 10-year lifespan as well. But one final note about b/c, from a personal standpoint-
Even if I had kept my old 60GB PS3, I still would've had a PS2 Slim hooked up all the time, on which I'd play any PS1 and PS2 games. The reason is that no matter how good the emulation was on the PS3, there was always something missing; i.e., sound cut-outs in Castlevania: Symphony of the Night . That's just one example. For me, I really don't care if b/c comes back to the PS3; I'll just always have the PS2 ready to go.