When Python comes up as an example of a problematic packaging ecosystem, Java often comes up as an example of it being done right. I think the key is the cultural difference you're pointing to. JVM folk are not tempted to stray from the JVM. Python folk think of Python as a convenient harness for that cumbersome bit of FORTRAN that they can't live without.

I only worked in a Java shop once, but I remember that they looked at me like I was an alien when I proposed that we involve a subprocess written in a different language.

At the time I thought they were insane for writing everything themselves but I've since seen how gnarly packaging can get and now think that they're... less insane.