You can just as effectively have HTTP sites that are simple listings of available software. I don't think FTP removal is really relevant here except for nostalgia.
FTP has some interesting features not found in straight HTTP such as charset conversion and my favorite the HOST command. HOST was the escape valve for commands you needed run that weren't implemented in the FTP protocol itself. I'm sure it's a terrible vulnerability now but it was fun to use and see what you could make a remote machine do.
Disagree. FTP as a protocol made self hosting all kinds of things much easier. We could soon live in a world where people self host their own data powered by protocols that will borrow heavily from FTP.
HTTP is one layer too low to replace FTP. HTTP can provide the transport but not the application semantics. We would have to agree on a protocol that uses HTTP to replace FTP.
That is a fair point. WebDAV seems to provide the listing and update semantics that you are looking for. WebDAV is widely supported by webservers so I think it is a great replacement for FTP.