Earlier quoted context omitted.
Phones just don't make a good analog to computers with a robust file system browser. My experience is if you're downloading something on a phone, it's never going be used again. It will sit there until a factory reset. How many restaurant menus have I downloaded read once and never cleared off? I don't know. I also don't care. If I did care, I would want to use "Save As..." and save to google drive.
Phones have as robust file system browsers as desktop computers. It's probably just that the users of phones are not that "robust" and organized to care where the files are.
On the android side the file browser that comes with the phone (if any) is bare bones. This combined with various sandboxing can make it pretty annoying to know exactly where your files end up.
Then there is the fact that the small UI on phones simply isn't all that great for browsing a large list of files.
So, putting it squarely on users isn't correct imho.