Can bus is a bus. You don’t need a dedicated run of wire per device. You can have a single loop that goes around the whole car that everything is connected to. Things that are “on the way” to others are relatively “free”. Compare this to an independent point to point wire for everything that’s under control.

This is trivially observed if you take a moment to compare a modern day wiring harness to something older, while considering the functionality provided by the later.