There are use cases where a thread pool doesn't solve your problem. If you're handling a few short-lived connections at a time, it's more than enough, but if you're developing something like a push / messaging / queuing service, with thousands of clients connected for hours at a time and receiving very little data once every few minutes, a thread pool won't help you.
I can run millions of goroutines on a laptop. These get mapped to a relatively small number (number of available CPU cores with default settings) by the runtime.
