Slavery typically means you have a boss who directly tells you what to do, and not only during your working time but 24/7.

Not at all. Slavery is human ownership. Slavery is the right to compel by force.

The interesting part of Molyneux's analysis is looking at slaves as a herd the human rancher wants to extract value from, and showing how the value extraction strategies have improved over time. Or at least arguing that they have.

What you describe is just one of many strategies of extracting value by force from your property.

It would be very interesting to see a real accounting analysis of slavery over time. What were the margins for a US plantation? For serfs? Has anyone actually seen these numbers?