Stone age tools
vi is a stone age tool, emacs is probably bronze age.
I've been using emacs (and vi/vim, if necessary) since the 80's, but you I know for a fact that I can produce better code faster in Java or Scala with modern tools.
You can carve what ever you want out of wood with a flint axe, but you can't build a 747 or a skyscraper with one. You can strap whatever you want to vim by way of plugins, but it's never going to be the sort of power tool that IntelliJ is.