It sounds like hold music.
But from the 80/90s!
Macintosh Plus is doing something legitimately specific and relatively new, enough to consider a subgenre, yet the ones you point out are just good ol ambient. If they are both to be considered in the same boat because the only actually intended defining characteristic is wherever they get their samples from, I'd argue that is not enough to define a subgenre but more like a pretentious ideology they use to create music along parameters that fit different existing subgenres.
I'd say it's much more pretentious for you to tell musicians that they're not actually what they believe they are.
Not really gonna continue arguing that something isn't vaporware enough for you, though, if you wanna believe that it isn't then be my guest.