I don’t know enough rust to comment on that part of the article but I’ve run GC-based systems at scale and load and the remarks about that do not match my experience at all.

I've coded performant applications on an OS that used channels and it sucked. It just got in the way and was confusing to engineers used to lower level constructs. "Just get out of my way!"

I think rust async is hard.

And that's what it comes down to. 99.9% (maybe more nines) of people do not need that level of control. They need conceptually simple things, like channels, and GC, and that will work for nearly everyone. The ones who need to drop to rust either have the engineers to do that, or their problem is intractable (for them). I pity those who drop to rust prematurely because it's cool.