If the Chinese Gov cuts the power , you are looking at over 65% of the bitcoin mining disappear overnight.
Are you sure about that? What proof do you have that 65% of the hash power is actually running on ASICs in China AND is running in farms that the Chinese government can identify, find, and shut off power?
I have no idea as to the accuracy of the 65% number khaos77 cited. The Chinese government knows a lot of information on their citizens and others within their country, it is known to put
spyware on some tourists phones, and may have
spyware on large portions of its citizens phones, or otherwise surveil its citizens.
I don't think the Chinese government could shut down, or commander 100% of the ASIC farms located within the country, but it could probably control nearly all of them. If the Chinese government was involved in some attack on bitcoin/crypto, I believe it would take control over miners, not shut them down. Shutting down miners would not be very effective for reasons you cited below, but controlling miners could harm confidence in bitcoin if many blocks are orphaned, and/or many transactions with confirmations become unconfirmed.
This alone will freeze the network, and no transactions will be possible for months, unless the hard fork difficulty adjustment occurs.
Nonsense. Even if we accept your assumption that China could identify and shut power off to 65% of the global hash power, that would simply increase the average confirmation time from 10 minutes per confirmation to 28.5 minutes per confirmation. 28 minute confirmations aren't going to "freeze the network" or result in "no transactions . . . possible for months". That's just silly.
Furthermore, it's going to take less than 40 days until the normal difficulty adjustment gets things sped back up to an average of 1 confirmation every 10 minutes.
There are currently some miners turned off because required operating costs (such as electricity) make them unprofitable to operate based on electric costs, estimated mining revenue, and the price of bitcoin. Some of these miners will be turned back on before the difficulty adjusts.
If the number of blocks per x time decreases, that means, the supply of block space also decreases, and all else being equal, when the supply of something goes down, its price goes up. This means the price per transaction will go up, which means the estimated mining revenue goes up (from transaction fees). The increased additional estimated mining revenue may cause some miners that were previously turned off to be turned back on.