According to Walter Scheidel's The Great Leveler: Violence and the History of Inequality from the Stone Age to the Twenty-First Century, the answer is revolutionary violence.

It's a fascinating read. I very much recommend the chapter covering the Black Plague. Seems rather relevant nowadays.

Employers lost no time pressuring the authorities to curb the rising cost of labor. Less than a year after the arrival of the Black Death in England, in June 1349, the crown passed the Ordinance of Laborers:

Since a great part of the population, and especially workers and employees (“servants”), has now died in this pestilence many people, observing the needs of masters and the shortage of employees, are refusing to work unless they are paid an excessive salary. . . . We have ordained that every man or woman in our realm of England, whether free or unfree, who is physically fit and below the age of sixty, not living by trade and exercising a particular craft, and not having private means of land of their own upon which they need to work, and not working for someone else, shall, if offered employment consonant with their status, be obliged to accept the employment offered, and they should be paid only the fees, liveries, payments or salaries which were usually paid in the part of the country where they are working in the twentieth year of our reign [1346] or in some other appropriate year five or six years ago. . . . No one should pay or promise wages, liveries, payments or salaries greater than those defined above under pain of paying twice whatever he paid or promised to anyone who feels himself harmed by it. . . . Artisans and labourers ought not to receive for their labour and craft more money than they could have expected to receive in the said twentieth year or other appropriate year, in the place where they happen to be working; and if anyone takes more, let him be committed to gaol.

The actual effect of these ordinances appears to have been modest. Just two years later, another decree, the Statute of Labourers of 1351, complained that said employees, having no regard to the said ordinance but rather to their own ease and exceptional greed, withdraw themselves to work for great men and others, unless they are paid livery and wages double or treble what they were accustomed to receive in the said twentieth year and earlier, to the great damage of the great men and the impoverishing of all the Commons and sought to remedy this failure with ever more detailed restrictions and penalties. Within a generation, however, these measures had failed.

NoBoDy WanTs tO WoRk!!! lol.