The only proven practical purpose of crypto is evading regulation. So when regulation happens, it will effectively amount to making it illegal. Which won't kill it off, just move it into the black markets where it has actual use.

(I'm not implying any moral judgment here. Personally, I think it's actually a net positive given the amount of harmful regulation, both in national laws and in international sanctions. But that's precisely why it would be silly to expect it to not be driven underground by the governments in the long term.)