The author did mention emacs in the previous article where he talked about editors.

> The reason I didn’t stick around Emacs was basically because of its runtime choice, and ultimately, its Lisp ecosystem. The Emacs community is one of the best I have been talking to, and they have really, really talented people working on insanely complex topics, like turning Elisp code into native code (via C), including Emacs itself. But even with all those optimizations, the editor was still feeling too slow, and has a lot of background that you can feel. All the abstraction layers, all the Lisp macros (oh no), etc.

https://phaazon.net/blog/editors-in-2022

It already is! I've been building Emacs from the development branch for the last couple of years, and the improvements in 29 and now 30 have really been great. I barely remember the sluggishness the other comment mentions.