Comment by imiric

I'm not familiar with what UNIX or its modern descendants have or have not implemented. But why should Linux mimic them? Linux is a Unix-like, and a standalone implementation of the POSIX standard. The init system is implementation-specific, just like other features. There has been some cross-system influence, in all directions (similar implementations of FUSE, eBPF, containers, etc.), but there's no requirement that Linux must follow what other Unices do.

If you're going to argue that Linux implementing systemd is a good idea because it's following the trend in "proper" UNIX descendants, then the same argument can be made for it following the trend of BSD-style init systems. It ultimately boils down to which direction you think is better. I'm of the opinion that simple init systems, of which there are plenty to choose from, are a better fit for the Linux ecosystem than a suite of tightly coupled components that take over the entire system. If we disagree on that, then we'll never be on the same page.