Since when does questioning whether one person might move equal a mass migration or and ace-in-the-hole argument? Your language seems to indicate a sore spot has been hit.

We will see how it turns out. The main question is whether China has stolen enough technological ideas and knowledge to achieve escape velocity on their own. They've enjoyed free reign for 'partnering', coercion, & industrial & academic espionage for decades, and have indeed made very significant advances. That access is now being curtailed. If China has gained enough, and has sufficient financial assets, and can manage it, it should be able to bootstrap itself to next levels. Or, it may start faltering, in no small part to the inherent structural limitations of authoritarian states.

I think it is very much an open question

I'd still put my chips on the Democracies. Betting against the USA has always been a bad bet. But it's still been less than 250 years, so things may change.