If one plays enough games of Monopoly, one notices that there’s a phase of the game where players are fairly evenly balanced, with each one having a monopoly of properties, and everybody is collecting rent, and growing rich (thanks to repeated trips past “Go” and getting more money injected into the game). This is different from the final phase of the game, where one player has gained an advantage and is bolstering his wealth by bleeding everyone else dry.
And at the end of the game? Everybody is bankrupt except for the winner. And the winner cannot get any richer than he is at the end of the game, because there is no one left to pay him any rent.
So it is with our economy. The more people who are able to participate in it, the healthier it is, and the richer we all become (no, we don’t all have to be equally wealthy — we just all have to be at least solvent enough to participate). However, when fewer people are able to participate, there are fewer people to feed an income stream to the wealthy.
And once the wealthy manage to bankrupt the rest of us, they’re done.