The 10 year lifespan and the fact that they've been successful two times beforehand makes me believe that a PS4 will still happen. If Nintendo stopped at Gamecube, they would not have the success of the Wii. Sega stopped after two unsuccessful systems, I would follow that track record and say if the PS4 isn't successful as well, then they will quit. Trial and error in my opinion, PS4 will be great!