Python language development, in my experience, usually does move slower and is fairly backwards compatible. There is a large community on Python 2.7 and it is slowly moving over to Python 3. They've actually backported features from Python 3.x to Python 2.7 and Python 2.7 to Python 2.6 to ease the transition for developers.

I don't think it's entirely fair to group it with Ruby in this case.