This "winner takes all" aspect of social networking seems like exactly the kind of thing that government regulation and/or clever technical design should be used to prevent, to ensure continued competition in the market.
If it stops Chinese corporations getting an advantage great. But it seems ublikely to happen while US companies have the advantage, and once they start to lose it, it will probably be too late.
I don't see a way for government regulation to restrict social media companies from gaining market dominance.
Even splitting doesn't help. You can try to split the main social network off from some other profit-generating activities, but they would probably start those up again, after some time. You can't split the social network, because then users of the smaller parts just join the bigger part again.
Currently we don't know how to do it, except encourage new companies to rise.
If it stops Chinese corporations getting an advantage great. But it seems ublikely to happen while US companies have the advantage, and once they start to lose it, it will probably be too late.