It’s interesting that you raise collaboration points here. When Russ was getting in go modules design he reached out and I made time for him giving him a brain dump of knowledge from working on ruby gems for many years and the bundler introduction into that ecosystem and forge deprecation/gemcutter transition, plus insights from having watched npm and cargo due to adjacencies. He took a lot of notes and things from that showed up in the posts and design. When fuchsia was starting to rumble about dropping go I reached out to him about it, hoping to discuss some of the key points - he never got back to me.
I don't see the issue it being a fork, plenty of languages have multiple implementations, with various degrees of plus and minus.
As for the rest, thanks for the sharing the experience.
Similar to Longhorn/Midori versus Android, on one side Microsoft WinDev politics managed to kill any effort to use .NET instead of COM/C++, on the other side Google teams collaborated to actually ship a managed OS, nowadays used by billions of people across the world.
On both cases, politics and product management vision won over relevance of the related technical stacks.
I always take with a grain of salt why A is better than B, only on technical matters.