In my opinion it can't.
To me, best case scenario, it gets a very confortable second place everywhere but America, and maybe even a second place there; worst case scenario, confortable second place in Japan, unconfortable third place in America, and reasonably disputed second place elsewhere. But the truth will likely be something in between. Note that this means it gets second place overall anyway, but it might very well loose most exclusive games targeted for America.
Beyond that, the Wii already won, and will win more or less everywhere, DS style - which means there's place for PSP style competition and success from the PS360. Combined they'll do much better than the PSP actually, probably better than the Wii. Between them, they'll just have to split different regions differently.
Again, my opinion.
Reality has a Nintendo bias.