> For the first time in generations, peasants could make demands. They could walk away from one lord and find work with another who offered better conditions.

Unless you were English, where the lords with the power passed laws (binding other lords) to override your obvious leverage: https://en.wikipedia.org/wiki/Statute_of_Labourers_1351

... and that led to the https://en.wikipedia.org/wiki/Peasants%27_Revolt