Hasn't greed, selfishness, and disconnection from humanity destroyed the society and infrastructure of the U.S.?

Absolutely. There was a study done years ago concerning a community of wild monkeys. They worked together cohesively to care, feed, groom and otherwise take care of each other, the reasoning being that the survival and well-being of one helped ensure the survival and well-being of all.

But as tourists began to arrive and discovered the troop, they began to feed them and hunting as no longer an imperative. Suddenly there was enough for everyone and then some. So essentially, they didn't have to work as a group in order to survive. This led to more frequent fights, alienation, hoarding of food, refusal to communally feed and division into factions. What researchers were witnessing was a breakdown of a society resulting from greed, selfishness and the extravagance of being able to disconnect from one's neighbors.

Humans are no different. Using indexes of happiness, many times the poorest communities measure the highest rates of life satisfaction. Some think it's because so little time is spent seeking, attaining and using luxury. It comes down to the old adage, the simplest things in life are free.

Until we relearn how to care for our fellow man (humanity) because we depend on him for our own wellbeing and that of the community as a whole (greater good), we'll continue to disintegrate at a core level (societal infrastructure). Greed and selfishness are barriers to that basic decency.