TL;DR systemd is winning the developer mind share. Things being built like Gnome which require SystemD thus most things will need systemd.
http://erickoegel.wordpress.com/2014/10/20/consolekit2/comme...
"Ubuntu plans to take over maintainership (more precisely Martin Pitt from Canonical), to maintain it as long as they still need it, and will change the name while doing so."