That is a good mindset and you should hold on to it. Of course a gui can install a keylogger for you just as easily if not more so.
Trusted install sources, usually called repositories, are the way. Chances of malware exist, but they would require some spectacular shenanigans or conspiracies to set up.
Arcade games or handheld or video games didn’t have any storage. Even on old home computers if you’d want to program in a save feature, you’d need to instruct the user to change to a fresh cassette for save. Then back to the game tape for reloading the game. And rewind and find the save on top of that to load.
It took a long time before floppies became ubiquitous, even longer for hard disks.
Well, they’ve probably been markets for some hundreds of years before they dug a parking cave underneath. Old cities especially get increasingly cramped with time.
It’s unstable in the sense that it doesn’t stay the same for a long time. Stable is the release that will essentially stay the same until you install a different release.
Sid is the kid next door (Iirc) from Toy Story who would melt and mutilate toys for fun. He may have been a different kind of unstable.
Though this reminds me that I remember getting my first skis. But don’t remember learning to ski in particular. Skis and snow has just always been there. I think I know where they are still today.