First of all, Tornado.Cash is NOT a privacy coin but rather a mixer protocol built within the ETH blockchain. Second, the sanctions were only effective against the mixer's frontend interface (because it was hosted on a centralized server) and the GitHub repository itself. But they didn't have any effect on the smart contracts powering the mixer itself because of their decentralized and censorship-resistant design. We've seen how the US has been taking a strict stance against crypto/Blockchain tech, especially when it claims that most people use it for "illegal" activities (money laundering, tax evasion, etc). I wouldn't be surprised if the government takes further actions against mixers and even privacy coins themselves in order to help "legitimize" the industry as much as possible. Some countries might copy the US whenever they seem fit to do so. Others will simply turn their backs completely against crypto (like China and Russia) in order to stay in power.

What matters is that the whole space remains decentralized and censorship-resistant so that it can counteract governments' efforts against it. Centralization risks will only make it easier for governments to shut down the whole thing. While I do believe privacy coins and mixers will face further scrutiny in the long run, they won't disappear because of the way they're designed. Most (if not all) projects are open-sourced these days, so there's nothing stopping anyone from making forks in order to help protect our privacy. Considering that crypto has reached this far, I'd say it's too late for governments to do anything about it. Just my opinion