Let’s assume passkeys are the greatest thing since sliced bread.

Passkeys face the same problem as the USB-C rollout. Lots of different incompatible implementations and standards rolled under one name that are almost impossible to distinguish between. Very little education on how to use it and be prepared for it.

The difference is that the consequences of getting passkeys wrong for the user is significantly greater than getting the wrong cable, and while the latter can easily be fixed, the former may be irreversible.