Even async in Go isn't that good, ultimately. You can't monitor channels, you can't properly react to errors, you can't shutdown and restart them. A panic in a channel will kill your program. Etc.

It's "we learned about green threads and didn't bother to learn anything else" approach (also prevalent in many other languages)

It's more that it's CSP from early to mid 1990s, over which Go just added syntax sugar