It sounds like to me that the argument isn't that an advanced technology will go back through the ledger and identify people. It's that once people have been identified/linked to a public wallet, it's really easy to determine how they spent bitcoin because the record is public and permanent.
I agree, but there are people who create bank accounts (and I'm sure Coinbase accounts) with fake ID and use them for illegal proceedings. So while we can trust that the transactions log is accurate, it doesn't always prove a link to an actual person. My concern is someone having their identity stolen (or even just impersonation), used for KYC, then being linked to crimes without any deniability at all.
