No, it is the customer who affects the generation length, and from the current decline, it seems they do not intend to keep the sales up for another 5 years.
People will get bored with any console after 4-6 years, it is a law. Even now, people speculate about "xbox 720", "PS 4" and "Wii HD", even while predicting them for 2013.
I also predict that Sony will be the one to jump to the new generation first, except in the unlikely case of a later PS3domination.








