"Definitely not SysV which falls flat with dynamic hardware which is the norm these days on most systems."
I'm sorry, but systems with "dynamic hardware" are getting less and less common. Laptops rarely have PCMCIA or PCCard slots any more, and even if they have them, they are rarely used. Network cards used to be something you could unplug, today they are a standard part of your chipset, and even if you install additional ones, those are typical PCI-Express based by now.
I mean there used to be a time when your computer might have had 2 PCI network cards a non-PnP ISA one and one that was PnP and it actually dependent on the order in which the modules were loaded how those cards were named, however today you just have one network card, and if you have more that's all on the same bus, which will always be scanned the same way.
The same goes for "multi user" features, particularly "multi seated" features. Yes, that used to be a cool feature back in the early 2000s, but today you can literally buy a Raspberry Pi acting as an X-Server for less than a special multiseat graphics card would set you back.