Enough points in the recent discussion on the other thread.
You’d be allocating over half of your portfolio to one single country. Globalisation and international revenue/earnings exposure or not, it’s still just one jurisdiction, run by just one president, one parliament, and one foreign and (federal) policy. That does present cluster risk - think, for instance, the political “trade war” with China.
I am not saying this is necessarily a “bad” thing or one you shouldn’t do. Especially given your opening question though, it is maybe one you would want to give a few thoughts and some consideration - and then decide on consciously and opt for what you feel comfortable with.
That’s just to the high share of market capitalisation of US companies. So partly just because IPOs and having their stock traded on stock exchanges are so popular among US companies, that so many choose to do so. Does this make them “better” (performing) companies? Maybe there’s a correlation or you believe in one - but not per se.
Maybe. Though maybe there really are too many?
Anyways, that’s not still not a question or assumption I would call overly complicated.