I think that generics is really difficult to do well when added to a language later. At the very least you will have a lot of pre-existing code, including the s

I think that generics is really difficult to do well when added to a language later. At the very least you will have a lot of pre-existing code, including the standard library, that would have benefitted from generics, but doesn't because it was written before generics existed. And you will almost certainly have cases where generics don't mesh well with other features. I think that if go was designed from the beginning with generics, then generics probably would have worked better in go (and similarly for java).