[pravka]

>The only reason that that is not obvious is that Docker is piggybacking on the relatively excellent and well-developed package management of distributions like Debian and Fedora.

s/well-developed/widely-used

Just because a package manager has a broad user base does not make it excellent nor well-developed. pacman[1] user base is far smaller, but (IMHO) it's a much more refined package manager than apt or rpm.