I have a totally different take on this subject from anyone here. It's an idea I have been working on for a bit and am scheduled to give a lecture on. It is sort of a synthysis of various ideas. I'm not 100% sold on it but let me run it out.
I think that this has something to do with our collective unconscious. Not quite as woo woo as it sounds.
There is a long history of people, tribes if you like, having ceremonies where there is a great deal of giving. The general term for this is "Potlatch" after practices by some tribes in the Pacific NW. The general idea is that as cultures develop they create a "big man." When the group has an excess of food they will have a big feast and also invite some competing tribe and give them a lot of food. Then the invited tribal big man, and thus the group, is obligated to return the gifts and then some. If they can't they are 'humiliated.' Apparently this tends to go on in times of relative abundance as a substitute for war, it is a more peaceful way of achieving moral victory over some rival. Apparently when the PNW Indians populations were greatly decreased by disease they had so much excess food and other wealth that they could not give it away, they would burn it. Others have explained this in terms of 'conspicuous consumption,' "I'm better than you because I can waste more than you." Thus it kind of comes to a sexual display, like a peacock's tail. The gifting group benefits because they are all part of the same group, the Big Man is the symbol of the groups collective position. Thus the bigger and more wasteful the Big Man the greater the stature of the individuals in the group. The main points here is that this is, or at least starts as a voluntary action, and it has arisen in various groups in the world.
In larger societies we have things like Kings. It is the rare Brit who is not proud of their royal family. True, there are times when revolution occurs, but I'm talking about in times of relative prosperity as we are in the USA, indeed the entire Western culture, at the moment.
One may even think of the Marshall Plan as a Potlatch on a grand scale. We not only 'saved' Europe but we also had to rebuild them, and Japan, and thus we asserted our superior way.
In recent economic theory there is the idea that we need to 'make work.' Thus we have created the consumer culture. Like a fire consumes its fuel we pour our wealth (money spent in labor) into the fire of consumer spending. Instead of giving our food to others we buy useless junk. Who of us thinks that things are worth more than our free time? How many practice that thought? I believe that there is a American pride in having so much stuff, it gives us individual status "He who dies with the most toys wins." But also we elevate some selected individuals to extreme levels of wealth. These are our Big Men.
Forbs Worlds Riches Men
1 Caros Slim Helu - Mexico
2 Bill Gates - USA
3 Warren Buffett - USA
4. Mukesh Ambani - India
5. Lakshmi Mittal - India
If you are brutally honest with yourself don't you get a wee pang of "WTF?" by this list? A smidgen of jealousy?

If not you (because WE are all special

) then what about J6P? Check it out with your friends and co-workers. Read this list and see what their reactions are. I'm betting you will find some wounded national pride in hearing non-USA'ers on the list.
Thus we get stature from conspicuous consumption a la consumerism and through having the biggest Big Men. We bad, we bad, uh huh, uh huh!!!
My theory is that this is something that occurs only in times of relative abundance such as we have experienced for quite a while. Pax Americana.
I believe that none of this is on the surface of our consciousness but is buried in our group think/act. It is something that goes on at a genetic level, like chickens being born afraid of a raptor.