Fedora is pretty much vanilla GNOME.
They have minimize and maximize buttons ootb iirc. And probably a bunch of other stuff I can't cite off the top of my head. Arch is the one that has vanilla gnome.
And yes, pretty much all users install third party apps.
I think you have a biased view of an average user. Anyways we're getting off topic. The original argument being that tray icons are not relevant for most users. You have yet to cite a good example where the tray icon is necessary for the app to properly function.