I simply used it as an example of something that many would point to as evidence of Go's maturity level. If the language maintainers don't ever add generics to Go, I think I'd be comfortable with that. And if that's the way it plays out, eventually the design decision will be seen as firm and not a sign of immaturity.
But you have to be mature enough to jump over the shadow of your functional pride and write clean imperative code.
By that reasoning we can go back to assembly ;): you just have to be mature enough to jump over the shadow of your portability pride and write clean assembly code.
Abstractions exist to help us and in that respect Go feels like a throwback to the past. It's pretty much a Java 1.0 that compiles to machine code.
Maps are in principle trivial to parallelise. That would be a nice feature.
Will they ever add generics? Not sure. Will Java ever have proper first-class functions? Not sure.