Does vim really have an order of magnitude more users than emacs? Is emacs really lacking in mindshare? I have no real reason to doubt those claims but I find them kind of mind-boggling. I'd have guessed they were close to parity (for the first).
I can't immediately find the survey that struck me, but here's a Quora answer [1] that cites O'Reilley selling twice as many Vim books than Emacs, the Debian PopCon results [2] that are rather striking (but Debian PopCon has quite the preselection bias, and the data may not cover all sub-packages properly), and Ubuntu's results [3] are a bit harder to parse but also striking, with vim-common at 2714181 / 25488 installs / "votes" (regular uses), vs emacsen-common (the highest-placed "emacs" package) at 330647 / 1669.
[1] http://www.quora.com/Are-there-more-Emacs-or-Vim-users [2] https://qa.debian.org/popcon-graph.php?packages=vim%2C+emacs... [3] http://popcon.ubuntu.com/by_inst
C-h (+ k or m) is probably one of the first key chords you are to learn when starting emacs, from there everything is downhill.
People use what's available, having Vim preinstalled is a powerful headstart.
There are people who can program very productively in vi (I'm not one of them), so they can use vi for long and short tasks. I can program very productively in emacs but I don't consider it the right tool for quick one-off edits of something. Also vi comes with pretty much every UNIX-like base system I know of, while emacs is often off in a port system somewhere.
Using emacs in daemon mode with launchctl on osx and then making a shell alias and an automator launcher for emacsclient that just connects makes starting the new client so fast that I can use emacs for the quick jobs, too. The only thing I have to do now is get used to the emacs command equivalents for the quick edit jobs. For example, in vim I can open a file to a specific line, delete that line and then the first 5 characters of the next 50 lines, and exit the editor in just a few keystrokes, while in emacs I'd still be playing with C-h a and googling. The things I've spent the most time in emacs doing, common lisp, clojure, latex, and so on, have a very different set of common operations than the common sysadmin tasks I used vim for.
Here are the results from the latest SO developer survey. The data may be biased, but it looks like vim outnumbers emacs by 5:1: http://stackoverflow.com/research/developer-survey-2015#tech...
I don't particularly enjoy programming in vi, but I tend to do it quite a bit when making small changes to our codebase on my dev box in the sky and I don't want to deal with the overhead of starting an IDE locally.
It also stopped people from laughing at me when I ran nano. :p