Wil Gomez writing for Mac360 on the differences in obsolete, obsolescence, and vintage Mac (yes, there is such a thing). A Mac less than five years old is not considered obsolete.
Does that mean a Mac older than five years but still in good working order is obsolete? Yes. But if it still works and has been upgraded to more recent versions of macOS, then it’s likely performing as well if not better (but maybe not faster) than it did when original.
How most of us view obsolete.
There’s another definition for obsolete, and one I’ve used many times. A Mac becomes obsolete immediately when Apple introduces a new model that I want.