That doesn't ever have to be done.

Generics are a language level feature, so it must be done at the language/compiler level, otherwise people are forced to implement it using "go generate" or other metaprogramming. The standard library doesn't ever have to change in that regard. If people want a generic version of some function, they can just write it themself. Its possible/likely that more generic functions will be added to standard library, but its not a foregone conclusion that it needs to happen, or even should happen.