Wow learned a lot from this makes the exploring abandoned power station videos more fun, thanks!

Having less compute may mean even more cables: rather than having data sent over one cable then decoded, each line is either on or off, controlling: something… (there could be signals here just contemplating). In modern stuff the logic is condensed, with data running between, in effect these older systems were one distributed logic unit. Probably over simplifying hut think of an old motorcycle, many cables, because you have to run power and ground back and forth all the way from switches to lights motors etc and back again.