It's literally not a single solution. systemd isn't a piece of software, it's, like, 20 pieces of software.
People who think the init system is doing all of this have just not done even the bare minimum amount of research on the topic. Although, granted, the naming might not help.
Right, I guess I shouldn't have edited out my preemptive response to this: Of course the solution is internally composed of different parts. Most things are. People of course understand that those internal parts could be switched out for new parts that perform the same role in the overall solution, but that doesn't help when the disagreement is about the scope and purpose of the entire solution.
When people talk about systemd being a big ole monolith against the unix philosophy this is usually what they mean. And it's just not true. Like, theres no argument to be had because systemd is many pieces of software that do one thing.
My point was there is no systemd software. Systemd is a project naming convention with many projects under its umbrella that do not rely on each other in any way.
It's sort of like saying KDE is a whole thing because it has a text editor. Uh, no - KDE is a project, Kate is a text editor part of the k applications suite, which has nothing to do with plasma, the desktop shell. You can use Kate on any shell. You can use plasma without Kate.
People who think the init system is doing all of this have just not done even the bare minimum amount of research on the topic. Although, granted, the naming might not help.