What makes you say that?

I personally don't see Go and Elixir's primary domains as being equal, or one a superset of the other. So there's some argument to be made about the region where they overlap, but for something inherently based around fault-tolerance and distribution, seems to me that code written to run on the BEAM will be smaller and clearer and therefore more maintainable.

If I'm interested in building low latency and highly available web services it seems to me that both Go and Elixir are reasonable choices. How are they not the same primary domain?

But in any case, Elixir allows a lot more clever code. In my experience working on legacy software, clever code in a dynamic language is error prone and hard to refactor and maintain. Static typing can help, though, I've found this especially true in functional languages where you have a super smart developer do something clever that's hard to understand 5 years later.

What about distributed programming? The BEAM makes that sort of thing super easy.

Maybe Go does have good primitives or libraries for that, and I'm just ignorant of that. :)