What connection does the author draw between the Black Death and the shift of power in Europe cite evidence

This question refers to the text "The Black Death" by Margaret Gushue. In this text, the author describes the effect that the Black Death had on the population of Europe.

One of the biggest changes that came due to this epidemic was the fact that it led to a shift in power in Europe. Before the epidemic, the population of Europe was very large, and people often struggled to find work. Peasants had very little power, and were tied to the land they worked. However, the plague led to the death of a very large number of farmers. Because of this, workers became scarce. This led to greater opportunities in terms of work, greater mobility and higher wages. Therefore, it allowed the power to slightly shift from the landlords to the peasants.