At the same time, almost everyone in my family over the age of 60 who uses a non-Apple device has their devices completely sodden with crapware (and probably worse), to the point where they periodically have to taken them in to some sort of computer "repair" person to have them serviced (i.e., the garbage removed).

Some people apparently need help making judgment calls about what is and is not safe to install on their devices. I feel like Mac OS might strike the right balance here: you can install anything you want, but the OS throws up speedbumps if the app doesn't have the right signature, is not from the App Store, etc. These protections can be easily circumvented, but they send a signal that you should think twice about doing so if you don't really know what you're doing.