The usefulness of generics is easily demonstrated by Go itself — it has generics. It's only available to a bunch of magical functions (new, make, len, append),

The usefulness of generics is easily demonstrated by Go itself — it has generics. It's only available to a bunch of magical functions (new, make, len, append), types ("chan", "map", arrays and slices are all generic types) and keywords ("range"). But it's there, in plain view. Nobody can objectively argue that these aren't useful, or that they could have been implemented in a non-generic way without destroying the language. Wouldn't the utility transfer to the developer's own code? As for "let Go do its thing", I would argue that it already has been done: Plenty of pre-existing languages don't have generics. The lack is always felt, including in Go's direct precursors (such as Modula-2 and Oberon, languages that people later hacked generics onto because their real-world ergonomy as designed by Wirth wasn't great).