> They spent almost 10 years saying "we don't need generics", but now are implementing it
You're making things up. Not a single member of the Go team ever said "we don't need generics". In fact, the FAQ stated from day one that they "continue to think about it", and that "Generics may well be added at some point".
Go's dependency management was designed after analyzing Cargo and its problems: https://research.swtch.com/vgo-mvs