You may as well have asked this question in 2012 because it's exactly the same as it was back then, except now there is iCloud. Which in some ways is impressive.

Folders are generic labels, Photos, Documents, Downloads, and within those there is folder structure, but I've never seen any Apple user actually utilize them beyond the most basic organizational functions (and even that is not common). Granted, my demographic for the past couple years has been the elderly, but before that I worked with kids and it was basically the same.

If you use Apple products, you don't need folder structures because you can't take files off your device easily, it basically has to go through some form of cloud upload, if not iCloud then Google Drive. And you don't need folder structures for the same reason, cause why are you adding files to your device from somewhere that isn't iCloud?

This is only like 95% facetious, it's actually ridiculous how closed off Apple makes their products. By default when you make a spreadsheet with Apple's software it exports as a .pages file, instead of the actually useful .xls. This is for every. Single. Program. Word files, PowerPoint files, I'm sure there's even a PDF specific Apple file format.

As a user you can't access the filesystem. It's completely abstracted away. At least this was the case for the iPhone 6