Yeah of course I get your argument although we have rpm (or deb in debain based distros) across redHat and OpenSUSE it does not mean that the same rpm package would work on both systems due to distro specific aspects (like different root structures, init systems etc . . .), but that’s something for the package manager to solve, the package format could be agreed upon, which would ease the workload of developers and maintainers since the moment you know the target distros of a package they could see the base differences of said distros and add symlinks, dependencies, environment variables, services … as needed for the package.
This seems like it could lead to a whole lotta of conflicts, but I think if the daddy distros were designed all with one package format in mind, such format could be somewhat interoperable.