Why must high entropy passwords be rotated regularly anyway? Shouldn't they only need rotating after a certain number of incorrect logins? Shouldn't that number be decently high?
Regularly changing your password reduces the impact of an undetected security breach by shortening the maximum amount of time a leaked password remains useful.
Forcing people to regularly change their password means passwords get written down on a Post-it Note on the bottom of the keyboard.
Because people are just people, not superhuman remembering machines.