It doesn't if users are working around it.

Right. The first rule of password security: if you have a large enough user base, the odds of a user writing down a password increase, and as passwords become sufficiently difficult to remember, the odds approach 100% at some point that _some_ people are writing down passwords. No amount of defense in depth can protect the "I have a Post-It note under my keyboard" problem, if people can get into your building.

We've handled this by mandating password manager use and pushing length requirements to absurd levels to where it truly is easier to just use the manager, which has two factor.