What about the irony of pjmlp dismissing something because it's based on an obscure language going as far back as 2001? :-)
What about that then?
But I guess you're actually consistent: you often lament about people ignoring or reinventing approaches that proved themselves in older languages. Here are people that actually take clues from one such language, and you lament that they didn't do it earlier. I see now that it's not really ironic. Rather, you're seeing the glass half empty while I was seeing it half full.
While I am sure Java will get value types, it already has had several experimental releases and the features have been incrementally integrated, after the switch to 6 months release cadence, I am not so sure in regards to Go.
All we get is a source code repository full of comments showing how much is left to be done, if ever. Untouched since last August.