I've been almost exclusively an Emacs user since the turn of the millennium or so, even before I was a full-time professional programmer. I briefly tried out TextMate years ago, and I've tried out VS Code, but I stick to Emacs for day-to-day work, and the keybindings are pretty much hard-wired into me at this point.

At the same time, I hate and actively avoid typical tech interview processes, and I suspect my pass rate if I did a bunch of them would start out low and only grow after a while once I got used to "interview coding" (which is basically a separate skill from actual programming).

So I don't know why they see this effect. My first guess would be that it's a kind of survivorship bias; outside of the occasional splash of someone trendy inspiring some new users, using the classic Unix-y editors seems to correlate with older/more experienced programmers. Who, because they've managed to stick around as long as they have, probably can manage to get hired when they want or need to.