IMO, poverty didn't start at some arbitrary time; it was and is always present. The development of human civilization from tribes of hunter/gatherers to agricultural communities to the modern industrial society is the response to the question, "What's for dinner?"
In the oldest human colonies, if you weren't fleet of foot or didn't have a weapon handy, the answer to the question above was 'You are.'
Money and monetary systems are a relatively recent innovation. Money, in the sense of coins and whatnot, developed in Asia Minor in the first millennium BC.
Before that development, there was plenty of poverty and class systems (pace Mr. Graeber) to go around. The Egyptians and the civilizations living in Mesopotamia did not have money as we know it, but they did have rulers/priestly castes, scribes, artisans, merchants, farmers, and finally ordinary working stiffs and slaves. All had their prescribed spheres of living and associations. Even in modern so-called 'classless' societies (cf. the Soviet Union and China), there was a definite sorting of individuals into various groups. Before WWI, Russia was an exporter of grain; within 15 years of the Bolshevik takeover, there was famine and starvation in the Ukraine, which previously supplied much of the grain harvested by tsarist Russia.
Today, with all of the technology and scientific knowledge man has developed, the planet could be returned to widespread starvation in a matter of months if a natural disaster caused the loss of a significant portion of our agriculture. Man can only stockpile so much food because of its perishable nature.