So far as I'm aware, every mainstream language, including golang, that's addressed this question has chosen to solve it by monomorphising generic functions. This implementation was well understood when golang was first released, and it isn't remotely plausible that the authors were not aware of it.

> Also what breaking changes you are talking about I am not aware of any. Also there is no golang 2.0 yet.

An argument given at the time was that committing to an implementation of generics would potentially put golang in an awkward position similar to Java's wherein if the implementation turned out to be bad, the language would be stuck with it anyway for backward compatibility reasons. I am simply pointing out that, since both golang 2 and generics have been discussed roughly contemporaneously (generics landing shortly, golang 2 having first been discussed in 2019 and therefore presumably to happen at some point soonish), any initial implementation of generics would not have particularly constrained what the golang team is now doing.