> ...it's a comprehensive look at how you do routine sysadmin tasks. The kind of thing that Linux pushes off to web tutorials or stackoverflow.

A lot of useful material with near-official status is kept under the Linux Documentation Project, https://tldp.org/ They have a git repository at https://github.com/tLDP/LDP

There are some cases of real churn in Linux but they're rare. The new init systems and such come with plenty of useful features that simplify many administration tasks: the reason for people being so unsatisfied with them is that they bring lots of what's effectively cowboy-coded hacks and prototype-quality code in order to enable these features. But rewriting all of this stuff from the ground up with a clean, Unix-like design (or rather, Plan9-, Limbo- or Amoeba-like, given that Linux now supports the needed foundational features for these) while preserving its feature set would involve more rather than less churn.