This is a pretty strange hypothetical situation. "What if MS/Nintendo become more competitive in Europe/row" doesn't really leave much for discussion, especially when there's currently no reason to believe such a thing would happen.
A somewhat extreme example, but this is a bit like asking "What if MS gets their shit together in Japan? Are Sony/Nintendo in trouble?"
Edit: or are you asking what would happen if Nintendo were to dominate in Japan and MS were to dominate in NA? In that case, that's unlikely given playstation has always been quite competitive in those regions, but if it were to happen then it wouldn't mean much for Nintendo given how insignificant Japan has become on the home console front, and while it would certainly help MS, I think Europe/Row have a bigger potential audience so I wouldn't say Sony would be in a worse position than the other 2 even then. Of course as I said earlier, this whole thread is predicated on some pretty unlikely scenarios.
