antirez's original text editor was a full featured text editor -- meaning fully customizable (and fast!) syntax highlighting, and a very intuitive search feature -- written in pure C, with no dependencies, not even ncurses, and written in less than 1,000 lines of C code. And he wrote all this in a matter of hours.
This showed that fundamentally, a terminal-based text editor is trivial to build. Keep in mind, the text-editor market space is currently very sparse, with only a few real choices: Nano, Vim, Emacs, Notepad, TextMate, Sublime Text, and lately Atom, are the big players. antirez's work shows that, honestly, there's no real reason for the sparsity of choices. Writing a usable text editor is just not that hard.
And stevekemp's fork shows that it's still pretty trivial to add the kind of editor customization previously only thought possible in projects like Vim and Emacs. Think about it. Emacs came out in 1976! 40 years ago! But when people want an editor that's fully customizable, they go to that. Or to Vim, which, again, came out in 1991, 24 years ago! And trust me, setting up your environment so that it's actually usable, takes days to weeks.
Ironically, stevekemp and antirez's work, combined, shows that it actually takes less time to make an editor from scratch, than to customize Emacs or Vim to your liking! Granted, that's kind of a stretch, since most of us won't want to dive into implementing the concept of buffers.
More to the point than that, though, is that the top players in the terminal-based text editor slash IDE space, were written so many years ago, that the Internet was barely a thing at the time, that there wasn't yet a standardization on keyboards or terminals or even operating systems.
Things have changed. A LOT. It's time our terminal-based text editors caught up. But that doesn't inherently mean we have to start building everything on top of Electron. Terminals still work, and they're fast & efficient as hell.