> So the policy issue is a weak excuse for using different tools.
No. It's an excuse for avoid _changing_ tools. Big difference.
BUT what would really solve droping dpkg? Imagine if you wish that tomorrow Debian ditches the .deb format and converts overnight to RPM. Now what? Packagers still would have to make different packages for Debian (and maybe Ubuntu), SuSE, Fedora, RedHat, Mageia, etc. It's even worse, because ISVs have to package for every _release_ of the distro they target. What do have we won? Nothing. Maybe that is the reason it hasn't happened yet. Will it happen in the future? I doubt it. Look at SuSE: same RPM, just different. The tendency is to fragmentation, not convergence, in RPM land. There are even 2 different forks of the RPM format.
So, at the end of the day, the package format is not that important. And probably that's the reason why we haven't seen unification even after so many years of pushing in that direction.