>>cf100c+(OP)
That's funny, I did LFS a few years ago and specifically chose the systemd version so I could better understand it. I don't think this is a huge deal, I believe the older versions of the document that include SysVinit will still be available for a long time to come, and people who want it will figure out how to muddle through. If at some point in the future things diverge to such a point where that that becomes untenable, someone will step up and document how it is to be accomplished.