I think part of it is that mobile OSes have trained people to treat their computers like appliances. The way you do something is by getting an app that is tailor made to do that thing. There is no such thing as data, that can then be acted upon by different apps and services (I.e. files). What you have, instead, is Instagram, for taking pictures and sharing them with filters, and Pinterest for sharing random places on the internet, Notes for keeping documents, etc.
I think 1 striking manifestation of the loss of the concept of files is that if someone wants to share a Note from their iOS device, the most common way for them to do it is for them to likely take a screenshot of it and share that image.
Since conceptually a note is not a thing of its own, but rather a part of the Notes app, people rightly believe you cannot share it on its own, and so need to go with the all catching screenshot fallback.
I think 1 striking manifestation of the loss of the concept of files is that if someone wants to share a Note from their iOS device, the most common way for them to do it is for them to likely take a screenshot of it and share that image.
Since conceptually a note is not a thing of its own, but rather a part of the Notes app, people rightly believe you cannot share it on its own, and so need to go with the all catching screenshot fallback.