Eclipse is a dog. If you compare vim to other text editors such as BBEdit, TextMate, Emacs, Gedit, Sublime Text 2, e, etc. then your argument falls flat on its face.
The nice thing about vi is its ubiquity. I can ssh into basically every UNIX system in the world and be reasonably certain that vi will be available. The same can't be said for BBEdit, TextMate, EMacs, Gedit, etc.
I picked up vi because I was stuck doing development over SSH from my college's public computer lab when my PC died. I stayed because once I'd learned the keystrokes, it really was a pretty decent editor. I think that Eclipse/TextMate/Gedit/etc. have some nice points and are definitely better in some respects (like, say, visual presentation), but vi is Good Enough and available basically everywhere.
I like vim, use it daily for editing configs and such, and used to use gvim as my main text editor. Its ubiquity or usefulness is not disputed by anyone. I don't think that modes are stupid (though I don't prefer modes myself).
However, when developing locally on a relatively modern machine it does not feel any faster at performing basic tasks than other text editors. vim being optimized to run over 300 baud connections is not an advantage in what many consider normal, daily use.
Yeah I've been am emacs user for decades but I know just enough vi to be able to navigate and edit config files, for this very reason. You always have vi.
That depends on the language support for the editor in question. Emacs can check C and related languages on the fly with flymake. Emacs can also check JavaScript on the fly with js2-mode. Editors such as BBEdit and TextMate cannot do that as far as I know. I'm not sure about the others that I mentioned.
The sky is the limit with programmable editors like Emacs and vim. Like general purpose hardware and OSs, neither can do anything that the other cannot do. Emacs does have an edge but in practice people have been able to make vim do just about anything.
