The biggest reason in the long run is because Sony has so much more variety. Variety in in exclusives, more exclusives, and it's easy to argue that they have better exclusives (in the future of this current gen that is).
Sony also has more support in Europe and Japan which means that gamers over in America will get exclusives befitting of those kinds of games from both regions. Especially Japan, I cannot push this enough. MS has tried and tried, but even after getting as lucky as they could get against Sony last gen at the start, Japanese multiplats and exclusives still did better in America on the PS3 despite the smaller user base in comparison to the 360.
Sony isn't going to make that price mistake again, and even if they did, we'd get a repeat of the 7th gen. Tied, but with Sony having more incentive for anyone worldwide to get a Sony machine over a MS machine.
Lube Me Up
