Socialism is really an economic system based on equality, but as all economic systems require centralized authority and overseeing/supervising to maintain. As capitalism is a system of organized inequality, socialism is one of organized equality. Centralized authority creates an endless political inequality, in some way much worse than found in capitalism.
I will look up this work, but 7.5bil people can no longer survive at the rate of current land/water use, not for long that is. Even if development was to halt at this very moment, the planet’s resources will be depleated, and equalization of material conditions will never have enough time to reach the other half of the population suffering.