I don't think you have said anything wrong, for the record. Go outperforms Erlang, mainly because it is a compiled language. V8 is a JIT-compiler (and it doesn't even interpret per se). In other words, those two systems are usually much faster than the BEAM VM when it comes to raw CPU bound computation.
HiPE does help a lot, but even with HiPE you can't easily beat a language with a static type system like Go: You have much less data to shove around when there are no type tags needed on most data.