The beauty of go is YAGNI. Language design makes it much harder for people so do stupid and cute things.

During my design process if I start realizing that I’m missing maps, More expressive Types, Or more complex polymorphism. I ask myself if I really need those things.

If I really do. I move off of go.

That’s the beauty of the language. Go does not need more complicated language features because it’s can handle the majority of trivial software work without unnecessary complexity.

The language does not need to solve complicated problems.

Map function leads to poor code in Go. Function literals are verbose and inlining is far less agressive. It simply isn't the way of the language. Even python shuns map and filter in favor of comprehensions. A for loop is more readable than the lambda soup.