Why did Pope Pius XI want Reconstruction of the Social Order?

In the text Quadragesimo Anno: Reconstruction of the Social Order, Pope Pius XI examined the potential effects of laissez-faire capitalism as well as totalitarian socialism on human freedom, and argued for a solidarity-based social order. This text was written in 1931, and the social context of the late 1920s influenced this examination of different economic systems. Stalin's first Five-Year Plan was established in 1928, and the USSR's transition to a totalitarian socialist economy created massive social upheaval, nationwide famine, and millions of deaths due to starvation, forced labor, and the Great Purge. Within the context of this transition, as well as the Great Depression in the U.S. and the rise of fascism under Mussolini in Italy, examining the shortfalls of different socio-economic systems was a very relevant question. Pius XI wrote the text to promote an economic system away from the extremes of unfettered capitalism or totalitarian communist states, instead arguing for societies based in solidarity with freedom and equal opportunity for all people.