- Rebellious teenagers always want to establish independence from their parents. Giving up part of the money takes you part of the way there.
- It's hard to be friends with people much poorer than you are - they may not accept you, and you may have hard time adjusting your spending patterns creating various embarrassments. Pretending to be poorer significantly increases the number of people you can be friends with.
As to the deterioration of the elites, I believe that our country lacks raison d'etre, and absent a clear mission people to turn to scrutinizing wealth indicators, culture wars, and such to decide why they get up in the morning. The US used to defend freedom from the Soviets and that was a pretty solid mission in the mind of the missionaries, then it coasted for a while, then tried to fight the terrorism which frankly was never the proper scale of a mission, and now it's just adrift.