Most distros are interested in a "what's easiest for us?" approach. Arch maintainers directly admit to this as their reason for adopting systemd, they can just ship their distro with it and now it's the packages fault for misbehaving and they don't need to deal with it at all. It's the same reason they all use GNOME by default: It's a big suite of bullshit that comes in a great monolithic blob, so you shit with that and systemd and most systems "just work"
Which is fine on the surface. It's (for both GNOME and systemd) the maintainers god damned narcisstic approach to design that's the problem. If systemd were truly modular like it claimed, it wouldn't be such a problem. If it would actually maintain an open and compatible API instead of making pull requests on extremely well established software like TMUX to fucking change themselves to accomodate systemd, or even making pull requests on the kernel its god damned self to work better for systemd, it wouldn't be a god damn problem. Let me repeat that: The developers of systemd have requested *KERNEL LEVEL CHANGES* so that it better fit THEIR design for an init system and watchdog. If that doesn't strike you as absolutely fucking insane then you're either braindead or not thinking. GNOME is almost identical to this thinking in that they expect software developers to program specifically around what GNOME wants rather than providing a generic, reusable API, so now everything depends directly on GTK bullshit.