I'm not convinced this will occur, even in the US. So many variables are involved with the "long term" and a lot can change between now and then. We will see. Even if Xbox does have the advantage, I believe it would be so inconsequential that the "lead" wouldn't even matter.
Well the lion's share of my friends are either staying with Playstation or converting to Playstation - that's a significant number. The diehard Xbox enthusiasts and anti PS people in my circles will not change though, so that's around 2 guys.
Pachter is right to an extent about some people getting all machines. Right now the PS4 and Wii U are what drive my interests, but I won't rule out a One if the software is compelling. MS need to give me at least 5 good reasons to get one and as long as my friends go that route I'd consider. When you're getting older and your friends are moving around the world "console wars" matter less, and the platform(s) you can play them on matters much more.
Playstation = The Beast from the East
Sony + Nintendo = WIN! PS3 + PSV + PS4 + Wii U + 3DS
