Not because the Python maintainers are intentionally doing a bad job, it's just that their mission isn't to substitute for your research. To them, "Does last year's Python script still work?" is always higher priority than "What's the best way to do it today?".
And what Python's security team decide constitutes a reasonable security fix may conflict pretty badly with what you need.
I would assume the Python devs review the code for a package before including it in the standard lib, right? That seems like a pretty big deal, well beyond someone just telling you that they tried a package and it worked for them.
It doesn't make as much sense for Python's standard library where you'd need to be paying attention to goings-on in the community to know if one of the batteries that are included has been judged expired and will be removed.
Give me a batteries included standard library please - much easier to audit and track.