https://homepages.inf.ed.ac.uk/wadler/topics/gj.html
Before Featherweight Go, there was Featherweight Java.
So maybe a language designed in 2012 (v 1.0 release year), should learn from history instead of hand-waving it away as needless fluff.
> In retrospect, we were biased too much by experience with C++ without concepts and Java generics. We would have been well-served to spend more time with CLU and C++ concepts earlier.
https://github.com/golang/proposal/blob/master/design/go2dra...
And not all on the team were convinced even after Featherweight Go, here Rob Pike,
> I think the transition to getting polymorphism into the language through generics is has still got some years to work through there's still things that don't quite work right