This thing shatters every time developers are told that they have to learn how to make operating system packages. As a developer myself, I cannot come to terms with that since OS packaging is a tool for developers and since it's easy to learn.

I mean, what and the how and the why?

It's supposed to be a team decision. If the team decides to use packages, then at least someone has to be able to implement that into the workflow, release and deploy process. If the team decides to not do RPMs or DEBs, then they have to solve build/deploy/release some other way.

For example since Docker I haven't even touched spec files or fpm ( https://github.com/jordansissel/fpm ).