[gonewest]

Well, look at the home page for Atom. It describes itself as "a text editor that's modern, approachable, yet hackable to the core."

They then call out features like cross platform editing, a package manager, smart autocompletion, file system browser, multiple panes, find and replace, themes and customization. If this list defines what they mean by "modern" then Emacs has been modern since before modern was a thing text editors needed to be.

However "approachability" is the one characteristic that stands out because it's subjective and that's telling. I would guess most people who aren't already familiar with Emacs find it daunting, just a little bit too different from the rest, and I can see a natural reluctance to invest time in learning something so different if the outcome (how productive will I be?) is unclear.