Honestly, I would in theory agree that releasing in the biggest territories first and leaving some smaller countries out to have more supply for those bigger territories is the smarter way of doing things. I don't think that very many people will change their mind and buy the more expensive X1 over the PS4 because it's in stock though, some will but not enough to make a real difference.
But seriously, I don't see how it even matters in this case, neither of these consoles is getting a significant advantage over the other this holiday season, in none of the markets. Both are doing well now and in the long run it really doesn't matter who comes out on top this christmas, the generation could still go to either of the two.