A major factor is that in many/most area and periods a low-ranking member of the society (even a serf or sometimes a slave) was able to move, for example in ord

A major factor is that in many/most area and periods a low-ranking member of the society (even a serf or sometimes a slave) was able to move, for example in order to escape from to much hardship by crossing the domain boundary (in stealth mode). This established a limit to the hardship enforced by a local power: too much of it, and too many will defect, either to the wilderness or to join another lord's domain (for example in some march). This is less and less an option, as technical progress helps enforcing a rule. We sure can read, however for many/most of us it is mainly "Manufacturing Consent" all day long, and thus a way for the establishment to manipulate us.