I admit the convenience is not the same, but this was already possible with my first Android phone (2011/12ish). There was an app called "Wifi File Transfer" w

I admit the convenience is not the same, but this was already possible with my first Android phone (2011/12ish). There was an app called "Wifi File Transfer" which would expose a web UI in the local network to download and upload files to the phone's storage. First I only used it to upload music to my phone (faster than USB1.1 or even USB2). Then I found out it also works fine when creating a WiFI AP/Hotspot and allowing other peers to connect to it.