"it just works" happened, combined with app-centric OSes.

Technology now caters to everyone, not just geeks.

It must work, even for grandmas.

Hence, no tinkering is needed, and many times isn't even possible (iOS, for example).

What really stumps me is that people don't know or understand basic filesystem structure.

They don't know about files/folders any more, as is the paradigm on desktop, in contrast with app-centric OSes.

They know apps, with their content. Many don't care to have their files offline, saved on disk, back them up etc. They work with them in the context of an app, and assume the app will always be there with their files, notes, documents, photos.