FTP was created 52 years ago. SFTP[0] Has been around for nearly 30. The latter is usually how I transfer files between two machines that I can connect to each other.
So your story is that when I turn up to a new university and want to send my powerpoint to their computer, I just call the support staff and tell them "install mDNS and a GUI"?
If the computers don't already have mDNS and a GUI, they should start with installing an OS shipped in the last 20 years, yes.
My point is that the technology to do this is already everywhere. People who control the software that runs on most computers would rather it be less convenient so they can push their own "solutions" to the "problem" though. Airdrop is a pinnacle example of this.