Actually it would kinda stand to make sense for devs to put all their focus into the ps4 as it is supposed to be much easier to work with. That in turn should make their jobs faster and more efficient, thus making developing game titles cheaper. Thats been arguably the biggest challenge from a developers standpoint with the ps3.
it was a challenge but they have had that figured out for awhile now...
If the PS4 / PS3 relationship goes the same way the PS1 / PS2 and the PS2 / PS3 went, then I would say we still have time to use our PS3s.
WHile the gaming experience and overall games will obviously be better for the PS4, I am sure some good titles will continue to be released for the PS3. I bought my PS2 on Launch in October of 2000.
I held off buying a PS3 until the last possible moment, due mainly to the cost of a new system. As well, by waiting, I was able to forgo the bugged 40Gs and the overheating 60Gs. I got myself into a nice 250G Slim for $300.00. On launch, I would have only been able to get the hot headed 60G.
All this said, I was still able to get quality PS2 games well into 2010. While the PS3 games were much better, they were not that much better that I felt the needed to run out and drop $500.00 for a 3.
I don't know if I will be able to hold out for a PS4, as long as I did for the 3, but only time will tell.
Short answer; I believe the PS3 games, on a "quality" level, will last out for at least another two to three years past the PS4 launch.
If it were not for COD MWII and the impending release (at the time) of DS2, I might have held out longer on the 3, and waited for the 4.
what about the people who cant afford the ps4 until the slim comes out and we all know it will