c0rd on 25 December 2008
I always thought the answer was pretty simple: the 360 helps keep the PS3 alive.
Just look at the sales of the biggest HD games this gen has produced: GTA IV, CoD4/WaW, Assassin's Creed, etc. The PS3 has a huge portion of these sales, and as long as that doesn't change, things should be fine. The PS3 userbase will probably be nearing 30mil by the end of next year, which is easily enough to justify porting HD games onto it.
You listed many failed consoles, but didn't mention the Sega Genesis/Mega Drive. That system was stuck in second place, yet had a decent lifespan (could've been longer if Sega didn't screw it up), and the PS3 is on track to outsell it within the next 2 years.
