Surely the PS3 still has a lot of life in it. It's like the PS2, it lasted for a long while before they stopped making games for it. IMO I think the PS3 will keep going on till at least mid 2015.
With the PS2, though a lot of its staying power came from the fact that it was the only thing available to a lot of countries for the longest time. For example, Brazil didn't get the PS3 until 2010. I bet the PS3 will flare out faster than the PS2 did, mainly cause we've pretty much seen its peak potential, but this lukewarm reception to the 'next-gen' will keep it on store shelves for at least until its 10th birthday.