I don't understand. What about this thread would make you fear running rust? Fear of learning a solution to rusts memory model, and 'fighting with the borrow checker' as they say -- sure. But rust never claimed that you wouldn't have to climb a steep learning curve, it claims that if you do make it up then the result can't hurt you due to a memory fault. So "fallen from the light" seems a little overdramatic.
IMO fallen from the light sounds spot on (not gp). I’m shocked to hear the state of async from real practitioners saying to avoid it.
"fallen from light" would mean breaking it's safety promises. No promises have been broken, the async developer experience is just less than a silver bullet and needs a lot of work. If you're so disappointed by that fact that you'd say rust has "fallen from light" then you've not been paying attention at all or your expectations need serious calibration.
Fearless concurrency in respect to threading .... Not async