Whether you can fallback to not using biometrics is irrelevant to whether biometrics is equivalent to usernames or passwords. In fact, your point that one can fallback to not using biometrics once it is compromised proves that biometrics is not equivalent to passwords.

At no point have I argued that biometrics are equivalent to passwords. But to conclude that biometrics must be equivalent to usernames because of that fact would be a false dichotomy. Biometrics serve an auxiliary role in security as an optional, subservient supplement to passwords.

If you never use your password do you then expect to remember it?

Yes. If you read about how biometrics are implemented on handsets, a user is required to enter their password every time that the device is rebooted. The password is also required at random intervals, once every few days or so. And if the biometric scanners log a handful of failed accesses, the handset is locked and a password is again required to enter.

The trend is we are going to see more use of biometrics to authenticate.