But as an example, if you wanted to have any sort of higher-level management of goroutines (for example, a bounded number of background workers) you get to rewrite or copy-paste that code every place you want to accomplish that. A library couldn't exist to abstract away the idea of a pool of background workers because it can't know in advance what types you want to send over your channels.

Again, I wouldn't be surprised if post-generics there's a library now to do this for you. But for years if you wanted anything higher level than raw channels, you're basically on your own.