Laziness? It's non-trivial to migrate to Python 3 if you've spent any time building up any number of bespoke libraries. Look at it this way: 1) I can spend 2

Laziness? It's non-trivial to migrate to Python 3 if you've spent any time building up any number of bespoke libraries. Look at it this way: 1) I can spend 2 days writing, testing, reviewing and pushing code that works perfectly fine in Python 2, or 2) I can spend a couple of weeks+ porting all the libraries I need for the tool to add python 3 support, maintaining backwards compatibility, fixing tests, reviewing etc. etc. etc., then spend 2 days to write the actual code I started out needing to do. Which one do you think I'm going to be able to justify, given there is always a backlog of work? Multiple weeks of developer time is a non-trivial expense. There has to be a significant technical advantage to justify the effort and for a lot of things that Python is used for there just isn't enough of one. I'm not anti-Python 3. I like it, in fact. Where I can use it, I do. It's just a lot of the time I can't because of all of the associated extra work involved.