Systemd is effectively Freedesktop/Fedora/Gnome dictating how every last Linux distro is supposed to behave. And doing so by invasive dependency chains.
Observe how LFS now have two parallel books. One continuing the one they have maintained from the start, and another dedicated to systemd. This is a good indicator how invasive systemd is in the basic construct of a Linux distro.
My guess is, it's not as relevant because Mac OS isn't as widely used in servers as Linux.