It's not magic, but neither are any of the alternatives. There needs to be a compelling "my constellation of services written in a variety of languages, communicating via a half-baked homebrew collection of API calls beats a constellation of distributed Erlang applications communicating via message passing over the BEAM" to claim that Erlang has scaling issues relative to the alternative.

The reality is that asynchronous, parallel, distributed computing is hard, Erlang makes it easier. Not easy, but easier.