Warren, and other Socialists in the Democrat party are blissfully ignorant of the means by which Bezos, Gates, Rockefeller, and many others gained their great wealth: They figured out ways of producing or selling things cheaper or better than anyone else could, and millions of people paid them to do it. If people like Warren start to confiscate that wealth, the result will be that people will eventually pay more for less gain. That’s why Socialist governments always collapse.
An unfortunate side effect of this process is that others (like Romney, Steyer, Buffett, and more) can also use the same system to make billions buying up failing businesses and destroy the bad parts and their jobs rather than using their resources to make them better.
Still, the net result is a better, cheaper cost of living for all. Socialism fails that result for everyone.
Buffet is not like Steyer or Romney.