To be fair, apple devices have airdrop for transferring files, which works much more seemlessly than any kind of network drives I've ever used (and I'm using one right now).
The interface exposed is just not mounting a remote file system.
If it was a real computer with a 'real OS', I'd be able to easily set up network shares and transfer files over wifi, without even plugging a cable in.
I've been using real computers with real OSes for a very, very long time, and when someone says "hey, could you send that file to me," I confess my first thought is not, "Why, sure! Let me just configure a network share that you can mount on your system to do it, because that is obviously the easiest possible way I have at my disposal!"
Still can't just treat the phone as a drive and put files on there.
(edit: or trivially share a folder on the LAN over wifi, without even needing the USB cable, if you're considering the iOS device a 'real computer')