Under-rated points. The threat model of KYC coins is super important. If Coinbase (or whoever) knows you bought 10m sats, then it doesn't seem too far-fetched that an aggressive government will eventually want a detailed accounting of where they are now. They might not know the UTXOs, but they know what you had.

This is my chief worry about how things could go realistically. Someone always jumps in and says what an accounting nightmare this would be, how it's not feasible. I agree! Jesus, it's so confusing to keep track of your UTXOs if you did anything other than park them in cold storage immediately after buying them. But it doesn't have to be feasible, it just has to chill legitimate market use. If you can't buy them or spend them on anything without getting sideways with the government, hardly anyone will bother.

Btc won't "die" but I'm not keen on waiting out $500-$1k prices for the next twenty years, or moving to El Salvador or whatever.