The point about this not being a major geopolitical event is well-taken: that's both a reason China would do this (because they could score a cool $1T in winnings from their crime) and also a reason they would not do this (if the effect would be negligible, then why even do it).
How would they score 1T, such an attack will only make losses, them having 51% of the mining power doesn't mean they own the coins, at most they can harm the value but there is no financial gain in this unless they double-spend.
The fact that Bitcoin has marketcap over $1T is not making it important to global economy. Was $1T actually invested in it? No, it's just the result of trading at high price multiplied by total supply. Bitcoin could crash to zero tomorrow and it won't affect the global economy because there's like 200-300 million people who own some Bitcoin, and only some percentage of them would be ruined financially if that happens.
I think this is something a lot miss when somebody is buying 100k worth of Btc that money are not really in some bitcoin fund, the actual money is in the pocket of the guy who has sold that BTC to you, and by the time you move your coins in cold storage they could have already been spent on hookers and Lambos, and funny enough, they moved not to the lambo but to the pocket of the guy that sold it, so the money is no longer there, it's just a price tag that somebody else might honor but again, it needs money for it.
That is the reason if MS loses its coins you won't see the economy taking a 10 billion hit neither would a fall of NVIDIA cause a global recession on its own. Much of that 1.5t is in unrealized gains, money that was never there in the first place.