They already tried it before but they didn't succeed on killing it.
Some country even ban it but they couldn't totally stop the people from using crypto or earning from it.
They could only create FUD by banning it but it wouldn't kill it.
I think the creator of Bitcoin Satoshi Nakamoto took his time to first study the challenges Bitcoin, took time to solve most of these problems before finally launching Bitcoin and that's why it's been impossible for governments to kill Bitcoin despite trials from different national governments across to the globe. Decentralization of Bitcoin solved most of the issues had faces since it's innovation and wether governments like it not, Bitcoin one day will be accepted as a medium of payment across all countries of the world.