Indeed! I teach an introductory web design class for undergraduates and despite my best efforts it takes a lot of students the whole semester to figure out files and folders. If I had more time in the term, I think I'd dedicate a unit to it, just to get everyone up to speed — and I may have to do it anyway. In fairness to the kids, even Mac and Windows machines these days do a lot to minimize users' exposure to file structures in the name of usability. Meanwhile, the phones and school Chromebooks they've grown up using completely obfuscate this information.