Are they so different that it's justified to have so many different distributions? So far I guess that different package manager are the reason that divides the linux community. One may be on KDE and one on GNOME but they can use each other's packages but usually you are bound to one manager
Thanks for pulling corner cases from dark places… not sure if we misunderstand but my point was as written, you use the package manager/repository which ships with your distro. So the original quote was: