I'll be honest.
I don't believe I have the capacity to reliably preserve, in a secure location, recovery codes from dozens of different services over many years.
I suspect I'm not the only one.
There is pretty much nothing else in my personal life I have to do something like this with. The closest might be my physical SSN card or birth certificate. But that's one thing to keep track of, not a new thing every week or month to add to the stash. And even those, if they get lost, there is SOME way to replace them, usually.
We are asking people to do something that is not a thing they have practice at or otherwise have to do or are any good at or have the capacity for. And then blaming them when they fail to pull it off, where you're constantly getting locked out of things and/or constantly getting hacked, probably both at once.
I understand passwords alone don't work. I don't have a solution. I'm just predicting a very painful digital future for most people.
(My own "solution" is using Authy TOTP, installing it on multiple devices, figuring I will retain working access to at least one of these configured devices, and not bothering with backup codes. I don't know how secure it really is, or TOTP is in general, but it lets me keep using services that require it, without living in fear that I'm going to lose my phone and misplace the backup codes and lose access forever).