The issue is that the previous "multi-culture" really sucked real bad. It was a shit show, really.
systemd is rising the bar by A LOT in terms of systems management, and most alternatives are simply not keeping up.
But can you really blame it on systemd making a stellar job on its own?
If anything, we could blame it on the "alternative projects" doing a fairly poor job and delivering very little.
edit: systemd is so good that FreeBSD people have already started pondering if they should build something similar for themselves: https://www.youtube.com/watch?v=o_AIw9bGogo