How does the American Dream work?

It's the rather deluded idea that all hardworking people will become rich and successful.

Sometimes it is twisted into the even more deluded idea that if you don't become rich, it is always 100% your own fault

It use to work where you could earn your way up in the company  to become  a manager or even a CEO   Back in the day it was normal for someone to work 10 to 15 years with a company and to be able to pay off there  mortgage.  Those days are gone 

Not since about 1975. 

It's a dream and that's about what it is

It doesn't.  It's more like the opiate of the masses.  It could've done if the US hadn't veered horribly to the Right a few decades ago.