Basically, I think of the 51% attack as the 9/11 attack. Yes, it would break the whole cryptocurrency market and dump almost all crypto currently existing. But if I would be a miner, holding such amount of hashrate shouldn't be taken as an advantage to have war in crypto/digital economy. I know most Chinese are good in money making and doesn't want a short-term business. Hence, it would simply imply that they'll still continue mining without attacking the crypto community, as they would only earn less if they do so.

Also, Satoshi still has a block that's left unused with a lot of bitcoin on hold, which is a greater risk and a worst possible btc price dump attack.