I can use IntelliJ for anything from Python to Ruby to Java to Go to Haskell.
Sure it takes a little longer to start up than a no-plugin Emacs or Sublime Text, but it also does a lot more and I don't have to fiddle with it to make it work.
The Go and Haskell support is better in ST2 than in IntelliJ. For Python and Ruby, it depends. IntelliJ is unquestionably better for Java, though.
Also, consider that ST2 is in its infancy and how developed its language support already is (see SublimeClang, for example). As ST2 becomes more popular, it might compete with the most developed IDEs.
I think that's unlikely. ST2 is already exceptionally fast and complete as an editor. As an IDE, ST2 requires plugins. These plugins are written in Python (which can use libs written in C) as opposed to vimscript or elisp. Moreover, these plugins aren't required for editing text files (or having SublimeClang isn't going to significantly slow down editing python files).
Vim and Emacs kill that argument. Neither is slow, and both are older than dirt in computer years. Sublime Text may continue the march without becoming super slow as well. I'm sure a Java-focused IDE could be fast and excellent, but that's not their focus.
Sure it takes a little longer to start up than a no-plugin Emacs or Sublime Text, but it also does a lot more and I don't have to fiddle with it to make it work.