I understand that there's gonna be a lot of wiring, having done a lot of vehicle wiring myself. What I don't understand is how they ended up with so much more w

I understand that there's gonna be a lot of wiring, having done a lot of vehicle wiring myself. What I don't understand is how they ended up with so much more wire than necessary. Is it from putting wires in the harness that didn't actually need to be there, or is it from routing the harness in a suboptimal way?