You’re commenting on a post by someone that managed to encapsulate a fully functional instance of an init manager, ripped out all of its default configuration, and replaced them with dummy files - just to find out the whole thing works exactly as documented.
And now you seriously argue this is brittle, non-straightforward, inflexible, and hard to verify? For real?
If I ever have seen a bloody well designed software system, it is this!
However "multiple orthogonal multiple orthogonal executables" is just a strawman: their interfaces are unstable and non-straightforward, aand communicate over standardized IPC mechanismsnd one can't reliably replace one of them with an alternative. It's technically true but in practice not. This effectively makes it a huge, inflexible, not-easily-verifiable blob with wide permissions and, potentially, many bugs.
> and communicate over standardized IPC mechanisms
I've never seen that anyone could replace one systemd component with an alternative implementation. Did you?