I saw an interesting article about how a million line production codebase was able to run simultaneously in both python 2 and 3, so I don't see how you could call them "different languages with similar names."
Python 2 and 3 are nearly identical. Yes, there's some backward incompatible changes. It's nothing like the gulf between Java and JavaScript which are only related in that they use C-like syntax. Java and C# have more in common than JavaScript.
That is not correct at all. Python 2 and Python 3 have relatively few syntax differences. You could teach someone the key differences in like 10 minutes.
In fact, I would even say that the difference between Python 2 and Python 3 syntax is far less than the syntax difference between traditional javascript and the latest revisions to javascript (ES6+).