Comment by untothebreach

I would say you are right except in one case, which is scientific computing. The OP touched on it, but that is definitely the "killer app" of the Python ecosystem, IMHO. Not that the languages you mentioned don't have equivalents, but if you are a rubyist who just wants to do some heavy-duty scientific/data-intensive computing without stepping too far out of your comfort zone, I can see Python being an attractive option.