Seems more plausible that mixers and other techniques for evading surveillance would be outlawed, as I can't imagine a government giving up the blockchain data

Seems more plausible that mixers and other techniques for evading surveillance would be outlawed, as I can't imagine a government giving up the blockchain data on peer-to-peer transactions. Imposing a KYC regs and social credit scores on wallets would be another likely measure. The U.S. will probably lead with a ban threat, and then walk it back to these measures as "reasonable," negotiated solutions. I'm not advocating these, but if I had to bet where the puck was going, this seems more likely.