"but I don't see how what Erlang does give you is less useful (even though the particular structure is different) than what you get in other languages that lack static typing."

Well, this gets into quasi-religious debates about type systems. All I can really do is point you to the Python or Ruby class systems and ask you to compare it to Erlang. And also observe that I'm pretty tired of dynamic typing in general, and Erlang is even farther in the direction that I'm tired of than Python/Ruby/etc.