I don’t think the author of Life, Inc. actually asks that question, or states that they were, but let’s get some things straight:
Historically, the plague arrived after the invention of the chartered corporation, and after central currency was mandated. Central currency became law, and 40 years later you get the plague. People got that poor that quickly. They were no longer allowed to use the land. It shifted from an abundance model to a scarcity model; from an economy based on annual grain production to one based on gold released by the king.
That’s a totally different way of understanding money. Land was no longer a thing the peasants could grow stuff on, land became an investment, land became an asset class for the wealthy. Once it became an asset class they started Partitioning and Enclosure, which meant people weren’t allowed to grow stuff on it, so subsistence farming was no longer a viable lifestyle. If you can’t do subsistence farming you must find a job, so then you go into the city and volunteer to do unskilled labor in a proto-factory for some guy who wants the least-skilled, cheapest labor possible. You move your whole family to where the work is, into the squalor, where conditions are overcrowded and impoverished — the perfect breeding ground for plague and death!
No, England, indeed the world, was an agrarian society before and after the plague, the largest city in England at the time was London with 70,000 inhabitants, 90% of the population lived in the countryside, people didn’t move to cities in large numbers until the Industrial Revolution in the 18th century. Rushkoff also seems to claim the currency was grain, when wool was the big cash crop in England. Enclosure and intensive farming didn’t reach it’s peak until the 18th century, driven by the Napoleonic Wars (you’d be surprised how many social changes have come out of wars).
The plague halved the population, which meant farm labourers could put up their wages due to lack of supply, the King tried to step in a set their wages back to pre-plague levels and it caused a revolt, but after the plague conditions got much better for peasants, because before the land owners owned all the land, and forced people to work on it for low wages (and sometimes they gave them small plots of land which were used to feed themselves and grow crops to sell) after it became a labourers market. Before the plague serfdom (livelong servitude) was still rife, after the revolution it rapidly declined.
Corporations had nothing to do with the conditions in the Middle Ages. You could argue that in the Industrial Revolution greedy factory owners were a problem, but many also provided good accommodation and access to schools, other forms of learning and leisure activities.
Are corporations bad? No, people are bad, governments who lack political will to control and legislate corporations are bad, but the entities themselves have helped our social and economic development as much as hurt it.