You clearly aren't running extensive production systems with little administrative resources. Code is written 15 years ago, and it's still running. Any changes that break something are major headache, usually leading rolling things back to working version. Nobody knows or cares to fix those things to achieve compatibility with new version. This leads to situation where nothing at all is ever updated. And even known bugs and exploits aren't getting fixed. Oh well, that's business as usual.

But when I'm writing new code, I'm of course using Python 3.