Every language reinvent the wheel

And here lies the crux of the problem. Rpm and dpkg would need massive re-engineering to cope with what portage does, I suspect, while portage is massive overkill for what rpm or dpkg do.

And then one only has to look at Red Hat and SuSE - two rpm-based distros that (less now than previously) were pretty much incompatible despite sharing the same package manager.

Everyone thinks that rpm distros were mostly cross-compatible, but that was for the same reason that dpkg distros are compatible - dpkg distros are all (afaik) Debian derivatives. MOST rpm distros are descended from Red Hat, but SUSE is descended from Yggdrasil/Slackware (and the rest... I can't remember the complications).

Cheers,
Wol