OTOH, was there really a time when humans were not enslaving each other in any form? I don't mean in a wide marxist term like "wage slave", but more specific kinds of bonding and control. Liberal changes in Europe in end of 18th century / beginning of 19th coincided with imported slavery from Africa and new colonies. That is freer factory worker would gain their productivity and better relative freedom while producing added value to raw materials produced by serfs elsewhere.

In 20th century you either had direct serfdom in some countries like Russia, while countries like US owned slaves indirectly by setting up large-scale production in 3rd world countries and controlling their governments.

Today we could probably breakdown the supply chain so that the lower you go by the ladder of "added value complexity", the more interchangeable and less free the people are. On the top of such chain there are managers, IT people, accountants and various service workers for the above who enjoy freedom while the bottom half of the supply chain is much more prosaic and constrained.