Services usually offer a tokens which should be saved somewhere in order to reset 2FA. I agree, requiring users to keep tokens for every service is painful (see how many people had trouble not losing their btc keys when btc wasn't particularly valuable)

I've only gotten a new phone once. Was android to android. I was able to transfer everything from the old phone to the new phone as part of setup process

Granted, yesterday I had some trouble: my phone service failed to process a payment, so they disabled my service. Meanwhile I couldn't go in & review my bank info because I needed 2FA in order to login.. To make matters worse, the bank told me I needed to call a number for Loss Prevention Services to reenable sending money out of my account, & made me run around a bit looking for pay phones (surprise, they were out of order) before they let me use their phone