Go team said many times that generics are technical issue, not a political one. (see [1] by rsc (Russ Cox from Go team))
There are also stories like experience report of Cloudflare outage due to the lack of monotonic clock support in Go that led to introducing one. [2]
The way how Go team handles potentially tectonic changes in language is also exemplary – very well communicated ideas, means to provide feedback, and clear explanation of how process works. [3]
Plus, many people in Go community do not want generics in Go (at least, in a way they're implemented in other languages). Their opinion also matters.
[1] https://news.ycombinator.com/item?id=9622417
[2] https://blog.golang.org/toward-go2
[3] https://go.googlesource.com/proposal/+/master/design/go2draf...