I second this. Plus, I ssh into my own server, tmux att and launch vim there. It is available wherever with Internet connection for me.
Can you please expand on this? I'd say you're wrong, but I'm not quite sure I really understand what you mean.
http://stackoverflow.com/questions/3109847/is-there-any-onli...
That's from 4 years ago, and the latest answer from over a year ago; I wouldn't be surprised if the situation were better now.
I don't know about you but I find that I do 99.99% of my work on one of my machines (where I have control over what's installed and what is not).
So the issue for me is not if I can access the editor from remote, but if I can access/sync the data. (which dropbox solves for me).