>The introduction of the various storage abstraction layers like devfs and HAL, plus all the other monolithic subsystem daemons in the form of the *kits that emerged early on, foreshadowed what would come today, even if they were mostly manageable back then.
This seems strangely backwards -- a lot of the "let's make this into files" philosophy like devfs, /proc, et. al. borrows from Plan 9, which is arguably more Unix than Unix; systemd on the other hand...
GNU/Linux, although historically mostly abiding by Unix principles, has always had syncretic aspects as early as the desktop environments experimenting with various fat RPC protocols over 15 years ago, and likely other precedents earlier.
The introduction of the various storage abstraction layers like devfs and HAL, plus all the other monolithic subsystem daemons in the form of the *kits that emerged early on, foreshadowed what would come today, even if they were mostly manageable back then.