[isjamesalive]

The user’s password would protect the disk’s key, but would not necessarily derive it, I think.

[ArnoVW]

Generally the way you solve that is by having the low entropy key give access to a hardware-based key store, like TPM. Those can be made tamper proof and throttled. I.e. the key is destroyed if you try to access the store by probing it, and it is locked (temporarily) after n failed attempts.

This also allows people changing their password as you do not change the actual (strong) key used for the disk but the key used to access it.