This right here is the exact reason that I, as a fairly experienced and hopefully pretty good Python programmer feel absolutely no desire to learn Ruby.  It doesn't offer me anything in terms of making me think differently about programming than Python, and I don't see any particular domain (other than, of course, Rails) where it offers an advantage in libraries or anything.  On the other hand, had I stumbled upon Ruby first and then found out about Python, I'm sure I probably wouldn't feel any need to learn Python, either.