True, but they aren't readily apparent to someone who isn't digging through the weeds of both languages.

I looked at 'Hello world!' and FizzBuzz written in both Python and Ruby, and thought that the implementations looked fairly comparable. I haven't seen enough to convince me that Ruby is vastly different - not to say that it won't happen, but I haven't experienced it yet. I think that's why the gut reaction is to think of Ruby and Python as parallel languages.