[foob]

I think this says more about those developers than it does about Vim. In my experience, people who are highly effective at programming in Vim typically have it configured in such a way that it offers language-specific functionality comparable to any IDE. You don't get that out of the box (unless you use a Vim distro), but you are able to personalize it to your workflow more exactly than you can with an IDE. A junior developer probably isn't going to be more effective in Vim than an IDE, but a very senior developer easily could be. And somebody who is committing code with lots of obvious errors is almost by definition not a senior developer in my book, regardless of whether they're programming in nano, Vim, or an IDE.