The game files continue to work, even without an account actually. You can simply keep the old launcher and/or run the game directly. While I agree with you in

The game files continue to work, even without an account actually. You can simply keep the old launcher and/or run the game directly. While I agree with you in principal, the truth is that if you don't update the launcher it doesn't break - and if you do update the launcher it also doesn't break, it just requires you to complete an account migration.