I've never liked global comparisons for LTD sales (and even lifetime total sales to an extent) because they're misleading and never tell the whole story. Staggered launches have been the norm since forever ago, with the Switch being the first to launch in every region on the same day (though the Wii came fairly close, launching in NA, Europe, and Japan within a less than 3-week span, though smaller markets came months later). And such staggered launches have never been consistent from generation to generation, with the sequence of regions and the time gaps never being the same. Combine this with the fact that each region has distinctly different buying habits, and it's clear that it's impossible to accurately compare global launch-aligned sales in any meaningful way. That's why the only fair comparisons are the ones that focus on each region separately. And when you do that, it's clear that the PS4 is not selling faster than the PS2, at least not in the U.S. and Japan (in Europe it seems to be keeping pace with the PS2).
Indeed. Europe will be the one area to have a surplus at the end. I don't believe it will be enough to eclipse a total of 157m units, though. More room for price cuts, sure, but the PS4 will never be as cheap as the PS2 was either.
What can be taken from all this is the PS4 is still another monster console from Sony, but their days of dominating like they did with the PS2 are gone (competition has changed and Japan won't be the juggernaut for PlayStation it once was). 130-140m tops, but still an excellent potential result.