Console life cycle is 5 years average, although Sony claim that their PS3 have some figure around 10 years, i highly doubt that. (PC platform by next year would have been on par or faster with these new gen of console in terms of pure performance

)
But of course console isnt all about pure performance, still, 10 years is... donsnt seems possible at all, esp they are not alone with Microsoft xBox console competing with them.
Anyway, these new console can play back old games, or so I heard. Logically, shouldnt be a problem anyway. And so long as the old games still appeals to u, u can play them on ur new PS3.
Accesories, ok, maybe u can keep them in ur store room. But old games, u can play them if u wants to. If not, then thats the case of the games no longer appeals to u, which has nothing to do with console lifecycle. Its just the game itself.
just my 2 cent
My old PS1 spoiled already, but I still play gran turismo 2 on my pc thru emulator. the game still very much appeals to me