There's not much else of a way to do it any better. Not sure your exact gripe here, other than dogmatic.
> Violation of the zero-cost abstractions principle.
It's not a principle, it's just a benefit of Rust's design that you get often but not always. `Clone` is not zero cost, should we throw that out too?
> Major degradation in developer's productivity.
Yawn, speak for yourself. I implemented incredibly extensive firmware with Embassy (async embedded framework) in months instead of years for a custom PCB I made. Async was literally the last thing on the list that caused problems - in fact it sped up my productivity and reduced power usage of the board overall.
> Most advertised benefits are imaginary, too expensive (unless you are FAANG) or can be achieved without async
No, they cannot. You are so confidently incorrect to an impressive extent.
Stopped reading after that section. This person has some bone to pick and left level-headedness at the door in doing so.
I think you've misunderstood. "Zero cost abstraction" is not the same as "zero cost".