Depending on "which" miners are shut down there is some potential for problems - if it is/was possible to shutdown a large percentage of the hashing power of the network then the difficulty to could be too high for the remaining miners to continue the chain (without it being so slow that it's unusable until enough blocks are mined to reduce the difficulty).

There's also the issue that, if governments are seizing the mining hardware, if they gather enough of it they could perform 51% attacks against the chain to effectively prevent it from working.

this is quite unlikely though. For comparison, during the Bitcoin vs Bitcoin Cash wars in late 2017, the main BTC block time went up to an hour - and pretty much nobody noticed, because all the excitement of the crypto bubble was happening on the exchanges, not on chain.

If the US gov goes after bitcoin there won’t be any exchanges left. They claim jurisdiction over anyone that so much looks at a U.S. dollar.

It's not about miners but about the users/investors. If US investors - which make up a huge fraction of money bet on Bitcoin - are excluded, the value goes way down and makes it less attractive also to non-US investors; another major use case is remittances but if people remitting money from USA to their relatives in third world can't legitimately buy Bitcoin from their creditcard or bank account, then that makes it less useful as a money transfer vehicle.

Why would satoshi appearing destabilise the market and destroy it? Something I’m obviously missing!

"Satoshi" is missing and that is part of the allure of BTC since it started from nothing. No premine, no vc investment, no corporate backing.

That said, there is an early wallet that is attributed to Satoshi with a giant amount of early mined BTC in it. If it ever moves, people will flip out.

https://en.wikipedia.org/wiki/Satoshi_Nakamoto

"Nakamoto owns between 750,000 and 1,100,000 bitcoin. As of November 2021, that puts his net worth at up to 73 billion US dollars, which would make him the 15th richest person in the world.[21]"

It would be like knowing that 5% of all gold ever mined is hidden somewhere.

Stephenson's Cryptonomicon feels weirdly more and more prescient every day.

There are a large number of BTC that have not moved since its early days which are largely believed to be / have been controlled by Satoshi, and if they were to move now, there would most likely be some sort of at least temporary price shock because market participants have been largely assuming that they will never move.