This isn't quite true. 2FA still protects you from password breaches (and weak passwords, though you shouldn't have those if you're using a password manager).

Also, keeping 2FA codes in a syncable password manager is a huge boon for people who ever break/lose phones. Can't tell you how many people get locked out of their accounts because they lose their 2FA codes.

As an alternative, companies have to have a 2FA-reset process. The fact that such a system exists weakens the entire system, which is too bad.