And 3 had different changes than 2 (https://docs.python.org/3/whatsnew/2.0.html) though it is interesting that Unicode support was a big feature in both, and that many people still find Python3’s Unicode support problematic (e.g., http://lucumr.pocoo.org/2014/5/12/everything-about-unicode/)

But if an individual or organization does not find the python 3 updates and ecosystem a compelling upgrade over 2, “don’t update until the next big change” is definitely one option.