I usually keep my Macs for a decade or longer and there's nothing wrong with my M1 Pro MacBook Pro 16.
Exactly. It's just that Apple in particular has a habit of immediately forgetting that the prior model existed. It will still work fine and get support for years I'm sure. But we know how Apple then likes to start artificially limiting software features to newer versions. Probably won't be as severe with the Mac as it is with the iPhone though.
The big memory hole dump was all the Intel models. Apple dropped those things like a ton of bricks the second the first M1 Macs came out.