Imagine a country in which the very richest people get all the economic gains. They eventually accumulate so much of the nation's total income and wealth that the middle class no longer has the purchasing power to keep the economy going full speed. Most of the middle class's wages keep falling and their major asset -- their home -- keeps shrinking in value.
Imagine that the richest people in this country use some of their vast wealth to routinely bribe politicians. They get the politicians to cut their taxes so low there's no money to finance important public investments that the middle class depends on -- such as schools and roads, or safety nets such as health care for the elderly and poor.
Imagine further that among the richest of these rich are financiers. These financiers have so much power over the rest of the economy they get average taxpayers to bail them out when their bets in the casino called the stock market go bad. They have so much power they even shred regulations intended to limit their power.
These financiers have so much power they force businesses to lay off millions of workers and to reduce the wages and benefits of millions of others, in order to maximize profits and raise share prices -- all of which make the financiers even richer, because they own so many of shares of stock and run the casino.