Python Software Foundation survey finds that a significant number of Python developers are still using Python 2 for data analysis, computer graphics, and devops.
Not sure why it is a big deal for most things. I was a 2.7 die hard and was forced to move to 3.x a few years ago. Had to rewrite a bunch of crap at first but once it was done it's been a lot better than I thought it was going to be at first.
I get that. My job is mostly writing Python scripts to keep an old Fortran based framework going, so I cringe when people get married into a language like this. I feel that all code should be adaptable and be able to absorb upgrades and changes. But I certainly understand. From my perspective if they were to rework my old Fortran code, it would take them at least a year or more to do it well. Most companies don't want to spend that sort of effort.
Python's public API changes subtly, so minor changes in Python version can lead to massive changes in the version of dependencies you use.
A few years ago we developed a script to update Cassandra on Python 2.7.Y. Production environment used Python 2.7.X (it was 5 patch releases earlier).
This completely changed the cassandra library version. We had to go back 15 patch releases which annoying resulting in a breaking change in the Cassandra libraries API and wouldn't work on the dev environments Python.
Python 3 hasn't solved this, 2 years ago I was asked to look at a number of Machine Learning projects running in docker. Upgrading Python from 3.4 to 3.8 had a huge effect on dependencies and figuring out the right combination was a huge pain.
This is a solved problem in Java, Node.js has the same weakness but their changes to language spec are additive so old code runs on new releases (just not the inverse). Ruby has exactly the same issues as Python
Java has had some breaking changes, especially the move to Jakarta namespace for certain dependencies, (thanks Oracle trademark enforcement) but I have had other code taken from 9 to 19 with no changes at all. I have some dependencies that I haven't recompiled since 6 which still work in 19.
Now dependency dependencies, yeah that can get tricky to get them all the right version.
I swear it's just as frustrating as Minecraft modding and picking the right forge version for all the mods you want. And OF COURSE your 2 favorite mods aren't on the same version so you can't use them together. I'm legit learning to mod Minecraft just so I can port them myself.