> I personally feel the chances are slim that "familiar programming concepts" (i.e. as taught by most intro CS courses) are optimal by themselves.

On the other hand, Erlang has been out for ages and has largely failed to attract much adoption, so it doesn’t seem like the market finds it to be “optimal” either. Not that popularity is everything, but over time a language better languages should increase their market share, especially if your language got its start during an era where the competition was C and C++ and Java.

> And I know it's an old thing, but the fact that Go was once adamantly against generics...

Erlang not only lacks generics, but it lacks any static type system at all…