Richest - Those companies that create the products that the most people purchase or use  i.e. Microsoft and Google.
Poorest - Those that contribute the least in the creation of products and services.
Big Crash - If that is the price the USA has to pay for that country to have a 25% of the world's GDP, so be it.
Only in America:
"The typical poor household, as defined by the government, has a car and air conditioning, two color televisions, cable or satellite TV, a DVD player, and a VCR. By its own report, the typical poor family was not hungry, was able to obtain medical care when needed.The typical average poor American has more living space in his home than the average (non-poor) European has."
http://www.heritage.org/poverty-and-inequality/report/air-conditioning-cable-tv-and-xbox-what-poverty-the-united-states