Haha, grumpyfish, I daren’t even say “welcome to Fluther” xD
Anyway, if it were purely historical reasons than surely it must be rewarding for the RPM- and APT-based distros to collaborate on developing a single PM, instead of creating interfaces like PackageKit? Though this wouldn’t allow you to create one installer for all distros, at least it would make it easier for people to package their applications for different distros, since you only need to learn it once.
Also, why was APT created initially again? What was wrong with RPM at the time?
Oh, and I still sometimes hear “I prefer APT” (or something else, of course). Is that just nonsense then, or are there really still actual advantages of one over the other? (Like I believe Fedora recently implemented something so only changes to packages needed to be downloaded instead of the whole application again when a new version was released.)