It's interesting how much the problems with blockchain SSO mirror those of blockchain currency. In both cases, the goal is to liberate people from centralized authorities. And in both cases, the advocates seem both to radically miscalculate how much the benefit of that shift accrues to ordinary people versus abusers, and almost completely miss the benefits of central authorities, who have at least some incentive to make recoverability and reversibility accessible to consumers.

I don't doubt that there are things you do to facilitate account recovery on immutable distributed ledgers, but it just seems pretty clear to me that you're working against the design of a blockchain when you do that; the blockchain isn't doing much that centralized systems aren't already doing, and they're doing a lot that gets in the way.

Certainly, I wouldn't want to be the person whose job it was to explain to a SOC2 auditor how my company's Ethereum SSO system works.

I wouldn't stake real money on the value of ETH or BTC; the market can stay irrational longer than I can stay solvent &c &c. But I'd probably make a real bet on blockchain-mediated single signon never achieving significant adoption, for some reasonable definition of "significant".