Reich states that the richest 400 Americans have more wealth than the bottom 150 million Americans together.

That is true. If there are 400 Americans than there would be 150 million Americans

Ongoing civil wars western roman empire finally collapsed476 c.e. romulus, the last of theroman  emperors in  the west, was overthrown by the germanic leader odoacer, who became the first barbarian to rule in rome. the order that the  roman empire  had brought towestern  europe for 1000 years was no more.