Maybe governments won't be able to stop the widespread usage of privacy-oriented cryptocurrencies, but they could restrict their growth in many ways. As worldwide governments reach a common agreement to put an end towards criminal activity related to such coins, the development of the space will stale by a large margin. Still though, it'll be difficult to achieve a full crackdown on privacy-oriented cryptocurrencies because of their distributed and decentralized design.

Even if governments find a way to cease the usage of privacy coins (at least for the time being), people will always find alternative ways to use them. With P2P trading, decentralized exchanges, and more, it's widely possible to continue using these cryptocurrencies without restrictions. But, everything will depend on the people themselves, whenever they will continue to adopt privacy coins like Monero and Grin or not.

In the end, transparent cryptocurrencies like Bitcoin and Ethereum will always be admired by governments worldwide, while privacy-oriented cryptocurrencies will become an alternative payment system for people worried about massive surveillance from the government. But be aware, that privacy-oriented coins won't gain as much support and traction from the general public because of the misleading reputation given by governments themselves. Just my thoughts