As it's creator said, the main purpose of Erlang is not to be fast, it is to be reliable. Sure, you can throw a lot of processors at it, but at the moment we are still not there (I just bought myself a QuadCore, not a QuazillionCore), and other languages might be able to benefit from more cores, too (once they arrive).

You are totally right, scaling linearly is just a side effect of the shared nothing concurrency- and reliability-based programming model but it's quite a feature anyway!

Do you have data, or are you arguing that it should scale?

An important lesson I've learned is that just because you've written a parallel program, doesn't mean you've written a good one.