It's not always as simple as "this person downloaded an IntelliJ plugin, so they're clearly not using Vim". This is because Vim (at least, I'm not sure about Emacs) is often available as a plugin for most editors. Sublime Text has Vim mode built in.
For example: most developers won't think of using Vim to develop a mobile app. In the case of building iOS apps, I'm not even sure if not using XCode is a possibility. But, Vim-loving developers will install the Vim plugin for Eclipse, and XVim for XCode, etc.
Interesting. I've usually had the opposite feedback from Vim users. They'll complain that Evil or XVim only has 80% of the key bindings and commands that they use. Apparently the missing 20% is very frustrating.
Evil mode for Emacs is the only "vim mode" that I have seen that is even slightly acceptable to me. Viper was fairly shit, and everything else that I have seen and tried was just awful. The most you can typically expect is some loose emulation of a divide between insert and normal mode, and maybe half of the normal mode commands implemented, most incorrectly (not taking counts or not combining with movement keys correctly are the most frequent oversights).
I do mobile development. About 95% of my time is spent in Vim, the other 5% in eclipse for the few things that it actually makes my life easier for. If eclipse were actually more useful to me, that percentage would probably drop as it would cause me to bother setting up Eclim (I can't be arsed to right now, since that 5% is so low.)
For example: most developers won't think of using Vim to develop a mobile app. In the case of building iOS apps, I'm not even sure if not using XCode is a possibility. But, Vim-loving developers will install the Vim plugin for Eclipse, and XVim for XCode, etc.