Bold highlights are mine.
I think you’re glossing over a fundamental problem we have in OSM is that there is no facility for data model or data schema change. We just simply change things (or not) and leave it to data consumers to just deal with it.
If we are serious about having the ability to change the data model/schema over time, then the one feature that would make this able to happen without friction is some kind of versioning and backwards compatibility layer.
As a data consumer, I have no way to say “I’m consuming OSM version X” and expect any reasonable degree of stability. And there’s no way for OSM to say "We’re making version X+1, and in that version these tagging schemes will be replaced with those tagging scheme.
So now that I’ve described the problem, we just need to sit back and wait for @NorthCrab to solve it for us.
Please pass the salty snacks.