Comment by paleotrope

A skeptical read would be that the economics of Norman style feudalism heavily relies on the peasants to work the land. Obviously you need the peasants to stay in their place. If all the warrior caste have the same perspective, you can't be carting off the population and selling them off overseas, without some major friction. And if you are trying to "take" some land from another warlord, it's not going to be very economical for you to sell off the peasants, cause then who is going to work the land?