You want to manage GOPATH as if it were a secret key!? Not ever storing it in repos, having weird dotfiles storing them locally, having to set up a keystore cluster like consul in production? Yuck.
The point is it's a per-project config. And yeah, there's no reason to store "/home/artur/go" in my git repo - that wouldn't work for my coworkers whose names are not Artur.