My guess would be the ease with which one can make a derivative and APT. Red Hat has been a pain in the neck at times. I remember the CentOS people having to ju

My guess would be the ease with which one can make a derivative and APT. Red Hat has been a pain in the neck at times. I remember the CentOS people having to jump through some hoops because of some stuff Red Hat was doing. Slackware can be difficult to set up and use without a modern package manager like APT or yum. Anyone extending it and targeting users who don't want to muck around in dependency hell would probably want to bolt on a decent package management system. In that case, it's easier to just start with Debian.