>Try running any part of the systemd software suite on an openrc system and see how that works out?

Well from this POV it's kinda openrc's problem if it doesn't. What about trying to run any part of the Openrc software suite on an Upstart system? The question why would anyone sane want to is rhetorical tho...

Why obsessing over whether systemd is monolithic and in what measure anyway? There certainly ARE optional systemd parts. So it's correct to say it's not entirely monolithic.