Bitcoin network runs by Bitcoin miners and Bitcoin full nodes. Satoshi Nakamoto can not shut it down and no single government can shut it down because Bitcoin network is decentralized. To shut it down, it must be a massive global effort from many governments or all governments to shut down the Bitcoin network.
They have to block access to download Bitcoin Core and other Bitcoin wallet softwares too.
What if all the countries block access to the internet or decide to block Bitcoin? If only one country allows Bitcoin and there are a couple of running nodes, Bitcoin will survive. I don't think all the countries will agree to ban or block Bitcoin. Some countries are working on adopting Bitcoin and companies adopting Bitcoin as well. If only El Salvador does not agree to ban Bitcoin, it's enough for Bitcoin to be active. We don't need 15K active nodes. Indeed more blocks make the network stronger. But that does not mean we need them to keep running Bitcoin. The government can't shut down Bitcoin. Or else, they could have done this a decade ago when Bitcoin was slowly growing. They were unable to shut it down back then, now it's not possible anymore.