As I wrote in the comment you replied to, the screensaver is NOT part of the init system, nor is logind part of the init system.
logind is developed by systemd, but a separate binary. In fact, every systemd project is a separate binary, just developed by the same project. Systemd is as much a monolith as KDE is.
Second, this tiny little logind binary is separate from the screensaver. It does not contain the screensaver, nor the lock screen, nor does it link to them.
This tiny process spawns the session and screensaver, and simply switches between them based on a signal. It's the tiniest possible concept for handling this task.
In general, I'd prefer if you could be more specific about your criticism, e.g. how this separate tiny binary is a "kitchen sink" and the screensaver, which is entirely separate from logind and systemd, is "part of a megalith".
Presumably, it is part of a “megalith” because now my screensaver depends on some crazy login manager, which depends on a crazy authenticated ipc scheme that loginctl uses, and probably none of this works if I replace systemd with something else, so it all depends on running some busted dns client with a recent history of remote exploits.
So, instead of wrapping my screensaver in a small program that manages respawns on crash, you’ve arranged to force me to either have the screensaver unlock itself (since you ripped out the old simple wrapper), or have remotely exploitable network holes.
Also, due to systemd, the some of the ioctls you need for rootless X are needlessly declared “root only”, so to call them, you have to launder the call through some authentication daemon that has its own (not Unix) security model, and runs as root.
Finnally, I run this mess on a machine that is also an NFS client, and it frequently times out mid login / resume session, so you need to login like three times on a bad day because nfs takes a few seconds to stat something.
It was even worse with systemd aware desktop environments. There, instead of timing out quickly, it would sometimes hang for minutes, with per-user copies of what appeared to he the whole systemd stack running, and no logs anywhere.
logind is developed by systemd, but a separate binary. In fact, every systemd project is a separate binary, just developed by the same project. Systemd is as much a monolith as KDE is.
Second, this tiny little logind binary is separate from the screensaver. It does not contain the screensaver, nor the lock screen, nor does it link to them.
This tiny process spawns the session and screensaver, and simply switches between them based on a signal. It's the tiniest possible concept for handling this task.
In general, I'd prefer if you could be more specific about your criticism, e.g. how this separate tiny binary is a "kitchen sink" and the screensaver, which is entirely separate from logind and systemd, is "part of a megalith".