I think at least part of the reason is because they own it. Per https://www.statista.com/statistics/1200477/bitcoin-mining-by-country/ https://www.statista.com/

I think at least part of the reason is because they own it. Per https://www.statista.com/statistics/1200477/bitcoin-mining-by-country/ https://www.statista.com/statistics/1200477/bitcoin-mining-b... 65% of all bitcoin mining is in China, this means majority of newly minted coins are in China, but also they can launch 51% attack at any time.