Peasants who survived the plague were able to get higher wages for their work. Why were they able to get these higher wages?

Peasants were now able to demand higher wages and better working conditions as landlords were not able to replace them with as much ease as previously. As a result peasants would be able to afford better living conditions'. After the plagues land and corn were plentiful, rents and restrictions reduced and standards of living improved.

the noble might have thought that the system was far because they had lot of things and riches and the serf would have thought that the feudal system was un fair because of the way they were treated.