I’ll coincide with you in that first-aid-quick-repairs is something people should in the best of cases know how to do, but setting a envirental variable or installing a package is not a “simple thing”. I’ve worked with engineers that programmed math models for a living that had no idea what a enviromental varible even was. Yes is easy to do, but the concept behind it, what it is, what it does and why are not simple, without the right background or the will to learn about the topic.
And, about user and owner. Sure, I get your point and personally I share it. But again, that is an opinion, tell a non-interested-user that they don’t really own their rig until they know how to use the terminal and I assure you that most of them will disagree.
Edit cause I wrongly posted before finishing: Comparing uncloging -manually pushing and pull a bar- or chaning a light -turn left, change, then right- or a breaker -literally just pulling a tab up- are WAY simpler actions. Yes, running apt upgrade is easy, but how you know is all well? That it work? + if I run apt update everyday I see almost no diference in my system, why should I even do something like that