I’m not sure if that’s actually true...vim has a hard dependency on ‘vim-runtime’ which is actually pretty big (28mb)

Not counting system libraries, "vim-tiny" is about 2 MB: https://packages.ubuntu.com/bionic/vim-tiny

You are right the dependencies probably have a larger impact, but notice that emacs has a similar package emacs25-common (65mb) in its dependecy tree.