It's such a big failure we have never had successful 51% attacks. One country having a large % of the global hashrate power doesn't mean China is controlling BTC. It's not just 1 miner doing this. It's lots of farms doing so.

And then, remember any attempt of an attack against us will be counter-attacked by the devs with properly implemented "antidotes". Bitcoin is about being open-source and decentralized. What centralizing it does.. is it makes Bitcoin completely useless, just like all the other shitcoins we have around.