Good points! Thorchain (a non-custodial service) claims 1.9B total swap volume. So, while not viable today for billions of dollars, the Bitcoin -> Thorchain -> Tornado Cash pathway seems to be viable for smaller amounts. Which doesn't necessarily bode well for recovering stolen bitcoin (and other crypto) in the future.
A thief still has to figure out how to convert crypto to fiat. But I am assuming that there are jurisdictions where this is possible without KYC.