My understanding is that pointer types all use dynamic dispatch in practice, because they share the same "gcshape" under the hood, today. Obviously this is very coarse grained.

However, the article points out this will likely change in the future, since the compiler now has enough information to do so. The Go team made a good call imo resisting to optimize this. Now, they can observe how generics are used in the global Go community and then optimize using real world code.

In fact, optimize is an understatement, because dyn dispatch vs monomorphization is a trade-off between compilation time + binary size vs speed (as C++ and Rust programmers know too well). Optimizing early based on microbenchmarks would likely have given an advantage in favor of monomorphization, but may not be suitable for average-to-large binaries in the a generic-heavy future. I assume the team wants to find a good balance for the 99%, and avoid compiler flags, hint-syntax, profile guided optimizations and so on if they can..