Also, the question asked doesn’t actually care about FP. Go isn’t a functional language, bit neither is it OO.
My point regarding the number of FP languages that it is not a silver bullet, neither is OOP to be sure, but FP has its own set of problems hence the many different implementations.
Regarding OOP languages implementing classic FP features, which is true and a blessing! These are good features which IMHO gives more credit to OOP languages.
Making a new language doesn’t automaticly imply that some other language got something wrong.
Sadly, there seems to be almost no functional programming concepts supported that I'd use (map, filter, reduce, lambdas). I think the lack of generics and operator overloading might have something to do with that?