Up to a point. Even 15 years ago the issues were clear and people were having to work around them.
> There has been mistakes, like the OpenSSL "fix", but not many.
That was the single worst bug in a general-purpose computer system IMO, and a predictable result of the Debian way of building packages. But they never felt the need to change their policies.
> Build Python projects on Debian, using apt as you dependency manager works pretty well
Python has notoriously terrible dependency management. It's a pretty low bar.
> One think so seems to forget is that you can often pull in newer versions of libraries and other packages from Backports. That does mitigate some of the issues with packages being to old.
The fact that there is such a big ecosystem of workarounds for linux distro packaging should tell you there's something fundamentally wrong with the basic idea.