> The material standard of living of a homeless person in modern-day Manhattan is several dozens of times higher than the wealthiest of kings ten thousand years ago.
Why? It seems true for some of the decent definitions of "material standard of living" although certainly not all. What they really lack (relatively) is social power, kinship tie quality, and many other more important things than internet access, smart phones, and technology (all of which may correlate with depression.
It was here that I stopped reading.