Samsung and Intel are the other two closest fabs in terms of technical capability. TSMC is clearly in the lead right now. And while the gap is very large in technology cycle terms (they're between 1 and 2 generations ahead at this point), in real world terms (like... considering what a fucking gongshow China invading Taiwan would be), it's not -that- big of a deal. It'd be a major speedbump, but not world changing (as opposed to the other ramifications of an invasion).