Comment by surajrmal

There are other languages with green threads and folks are free to use those. Zig is trying to do interesting things with stackful coroutines.

I don't think I nor most systems programmers would have chosen rust if it required green threads instead of stackless coroutines for async. If you work on embedded or low level environments like kernels and whatnot, you need something that falls back to callbacks for async. I'm sure folks who work on servers would have been fine with green threads but they were not the target audience for rust. Being upset because you fall outside the target demographic of a particular language doesn't mean they made the wrong choice. It just means you should look for something else.