They probably do though, openrc defaults to sysvinit as its PID1.

I guess it's part of the confusion too, most of the systemd work was replacing the "rc bits" (process startup and management) not replacing PID1 itself.

I mean, before systemd there existed other initds. Upstart was Ubuntu’s for a time.

The creator of Upstart, Scott, explicitly said that he thought that systemd was better and that Debian and Ubuntu adopting it was the right decision: https://www.reddit.com/r/LinuxActionShow/comments/1xzfv0/ups...

I don’t really have a strong opinion anymore. Scott makes the right move here for professionalism and modesty, and Linux is more united on this than it isn’t.

Still, the spats with the Linux kernel team and the rest of the community has earned systemd a reputation I can only say it deserves, even if the initial ire drawn towards it was over the top. Systemd is not a project I have strong confidence in to act in the user’s best interest, based on what I’ve seen with handling security issues.

And much like systemd or openrc, replacing PID1 (init) itself was not the point of upstart.

It was redhat's also, albeit, for a very short time.