I dislike all JavaScript transpilers. I still cannot get my head around how CoffeeScript ever got so popular. The complexity and friction that transpilers add is not worth the tiny benefits that they offer. I've worked on many projects where I had to wait for like 20 seconds for the code to compile each time I made a change to it.

From my point of view, it sounds like the author of this article is merely feeling the reality catching up to the hype.

Transpilers like CoffeeScript and Babel should never have become popular to begin with. Something unnatural happened in the evolution of those projects which allowed them to capture a lot of attention very quickly; and much of the initial adoption was driven by hype and network effects instead of real needs.