China may have had a big impact on the market and the development of Cryptocurrency and Bitcoin but they are not the sole developer of it, any country can take the lead if they want to leave, and it's their loss their miners and investors have amassed huge money from Cryptocurrency, if China ban Bitcoin I don't think all their miners and investors will just follow, of course, they will find a way.
definitely, those miners will find a way how to continue their business. now, that they learned the world of crypto, they will always find a way how to go around their govt. that's not the end of their life in crypto. and yes, when one door closes, the other door will open. we are not solely depending on China here. remember bitcoin and crypto can exist even without them. there will be other countries that are more than willing to host their closed businesses. so it is not our loss but them.
so btc becoming worthless is far from happening.
Some of them already did, look at the mining power and you will see that it dropped a ton and then increased a bit, that increase is caused by some of them already finding a place. Also remember miner is not a person physically mining, it is a machine and as long as the machine continues to exist you could just plug it out of china and then ship it to some other nation and plug it in there, hence continue to mine without a problem.
Many of them are doing that now, selling their well used and old machines as brand new and selling it with brand new prices whereas it is already used for months now, that is the trick they do, then use that money to buy real brand new stuff, if you are stupid you do get fooled and buy, they apparently can find enough stupid people to sell a whole mining facility, I saw that in a youtube video. Long story short I am sure miners are doing fine.