You could make the argument that things were more complicated back then. They had a real need for well written comprehensive manuals. Nowadays I guess we don't

You could make the argument that things were more complicated back then. They had a real need for well written comprehensive manuals. Nowadays I guess we don't because they don't appear to be made much any more. See also schematics. I watch a lot, perhaps too much, of people repairing old electronic equipment. And they always seem able to whip out a set of schmatics to help them diagnose the problem. In some areas things get worse over time.