I agree no one can turn off bitcoin now especially now that there are countries that have legalized bitcoin. This is one of the shocking news for the development of bitcoin so for now I don't think there is a loophole to shut down bitcoin.
Some have given a way but those are just possibilities if something really has to happen as such.
A catastrophic dooms-day scenario on earth that shuts down the internet would be the only way the bitcoin network would be "shut down" but this is realistically outside the realm of possibility at this point.
Yes, that's one possibility but the chances of it happening is below to zero point and a decimal percentage.