It doesn't matter until it does. If the chinese government decides that open weight model releases are no longer allowed, that's a lot of companies that can't release new models. Same with the US government, etc. Having diversity is important.
However unlike the US models, China banning the release of new models would not break existing ones. Betting on US models only can get you locked out in just a few hours.
No, Open weights US models would not break as well - this isn't related to China or USA, it's about Open Weights and the fact that you can download the models.
It's a similar problem the human DNA solved by telling our teenage selves that our parents are dumb and we needed to move to a new tribe. Genetic diversity, but a digital equivalent.