That's the key. The poor are useful to business so long as they are a source of money and power. What happens if the time comes that the poor have nothing the rich want?
Probably not this time though
This time there will be no revolution but it will be televised. :P
The rich do not want anything you have, they want you. Body and soul.
Not in our lifetimes and certainly not in our form of society. Robots will only drive down the price of labor. People will always be able to supply labor at costs below the price of materials for robots.
Why? What critical materials do robots need that will always be more expansive than raising a human?
Also, from the point of "the rich" - the benefit of a robot is, that it will (stupidly) do as command, unlike a human. They don't have a family they want to take care first.
Whether it's gladiators or bum fights, the poor will ultimately be given a job. Robot wars was fun, but UFC has stayed.