I read it just the other day. Can't remember the source. Something like 60% of game revenues come from the USA. It could be very wrong. I don't know.
Probably not overall, because F2P and MMO's is pretty huge in China/Korea.
Just for consoles, it might actually be reasonable. Usually the USA is about as big as Europe combined as a console market if not frankly a little bigger AFAIK. At a wild guess I'd think sony's sales are like 40/40/20 USA/EU/Japan And MS's more like 65/35 USA/EU.
It will be interesting to see how this plays out. I doubt we'll ever be able to model anything but anecdotally we know if we hear people saying I bought XB1 bc my friend has it or bc I owned a 360... It could potentially have a meaningful impact on the choices consumers make which in part is why Sony really should have doubled down on free MP IMO.
I think I saw some analyst posted on GAF yesterday estimate PS+ brought in $140 million annually, vs $1.25 Billion for XBL Gold.
And now we all know why Sony put MP behind a paywall.