OpenRC and Solaris SMF definitely did their own thing. SystemV-init and the "run levels" concept was flawed from the very start when it replaced the previous BSD-style "single user" vs "multi user" boot up.
Linux only adopted SystemV style init because it was the norm in Solaris at the time. It is not a linux-ism.
As this article notes - systemd is actually fine as an init system and hardly anyone denies it. It's all of the other stuff (journald, resolved, timers, etc) + tight coupling + environmental assumptions that is the problem.