Sure, there are maturity differences but it's nowhere near so vast a difference as some claim.
These are just preferences. It's not a culture war issue.
However there’s fundamental difference: in a model of distribution by a distro the developer only produces a software but they don’t release it themselves. They provide source code and that’s it. Maintainers of packages for each distro vet new releases, test, and sometimes patch them so they work best within context of a given distro. So there’s extra effort spent on making sure the software is stable. In a model where a developer publishes their new release to some package repository directly (npmjs.com is just one of them, same applies to pypi.org, rubygems.org, etc) that extra “QA” by others than the developer doesn’t happen.