I'm sure some are quitting as it's summer time but it wouldn't be enough to drop the hash this much.  This is China.  Even Bitmain is stopping spot sales of new miners while they are likely dumping old equipment that they don't want to relocate.

https://finance.yahoo.com/finance/news/bitmain-halts-sales-bitcoin-mining-162000866.html#:~:text=Bitmain%20Technologies%20Ltd.,be%20run%20out%20of%20town.