The problem with underperforming agriculture and lack of nutrition was persistent in that system. You seem to assume that peasants under serfdom had easy low work access to food and everything. That is not the case. The land does not produce food for whole year without you working it a lot.

Peasants in serfdom had hard time to produce enough food for themselves.

Peasant did not tended to few million dollars worth of land. Lords were not giving land to peasants. Rather, peasants were sold along with land and belonged to the land. That is massive difference - serfdom was one step above slavery.