I find it funny that neither the original blog post nor the comments here really talks much about "Why Atom can't replace vim".
The reason why Atom can't replace Vim, at least for me, is Atom is painfully slow due to the gigantic DOM tree behind it.
(Remember that the slur against Emacs -- itself once considered by some too heavyweight to compete with vi -- was that it used "eight megs" of memory.)
For the uninitiated: http://www.gnu.org/fun/jokes/ed-msg.html
This page has lots more: http://www.gnu.org/fun/jokes/gnuemacs.acro.exp.html
Having said that I default to 'vi foo.txt' on the command line and feel like vi competency is a core server skill ...