Many things are designed by roughly the same kind of people in roughly the same area. They are blind to a lot of use cases. Besides, it's a government's mandate to cover edge cases. Businesses only do it when compelled.
They're banking on you upgrading your device before it dies, as opposed to e.g. accidentally dropping it onto pavement and cracking the screen.
Had that happen to me, I was saved by still having the backup codes + having some unholy Tasker + Pebble automations that let me operate the phone without display - enough to launch AirDroid, use it as remote display/input to enable ADB over WiFi, and then finally use scrscpy over ADB as a remote display/input that doesn't blank out on security screens and in Google Authenticator. Only at this point I was able to transfer all the other TOTP entries in Authenticator to the new device.
Lesson learned: 2FA with TOTP is a responsibility to be taken seriously, despite what security professionals would make you believe.