I'll throw in my anecdotal evidence as well then. At work use ruby for a lot of configuration management with puppet mainly due to it just being easier to just throw some extra ruby in place than shell out to another script. So ever so slowly we have been getting more and more ruby into our "enterprise".
We also have another more "corporate" type piece of software that uses python that gets... less use, but that is more due to it really being written in java and having performance closer to a glacier. Which is why we have puppet now in the first place.
I've used both ruby and perl for equal amounts of time, and I've recently started to use it at work to replace old perl and shell I have. That and I've switched vm's to rubinius so those old "ruby is slow" gripes to be honest never cause problems. That and having a jit+vm that isn't java on each of our os's is really awesome.
Don't get me wrong, Python is a great language but you are 100% right, there isn't much need for learning both Ruby and Python. They both are roughly equivalent featurewise, but they both take completely different roads about how you approach general purpose programming. That said I know both but rarely use my Python knowledge much. But it does have some great libraries out there for numeric computation/etc... I also know of a few companies that use ruby as their goto language to get failing (java) projects out of the door.
Disclaimer: I never use rails at all, haven't since I looked at it source in the 1.x days. Was REALLY put off with all of the monkey patching they did.