Sorry, but I don't understand your logic. Why would it have been a bad decision? and how would it have "muddied comparability"? PC games support granular improvements; support for a game doesn't discern anything. I also can't find anything referencing their "explicit" performance requirements.
Since they want to support a console like experience, a clear compatibility indication is important. Releasing new models with different performance characteristics every two years would make that compatibility discovery PC-like, not console like. So bad from that perspective.
> I also can't find anything referencing their "explicit" performance requirements.