That is true. I did this hoping to make the // feature less deeply
embedded in Emacs.
The code below is a really simple proof-of-concept handler. Load it up
and try it! To make this work for real, some extra effort will be
necessary to make it bullet-proof and to figure out the semantics of
filenames in ftp URLs.
I encourage people to keep working on this, and get experience with it.
If the problem can be solved and gives reliable results, I would be happy
to make Emacs support URL syntax.