How well do HTTP/2 handle the transfer of whole directory trees?
FTP is a pretty conceited protocol, and one that deserves to go away. People say it made more sense in the 80's, but I was there and even then *NIX/Solaris admins found FTP to be about as much fun as that IRC pingback identd service; which is to say not very fun.
I'm surprised to see WebDAV mentioned here, to be honest, I thought it was a dead horse everywhere except in enterprise.
The modern web is much more about routes, resources, and URLs than directories and files.