At some point, AI, robots, and automation are going to render the vast majority of jobs obsolete. At that point, the robber barons will consider us all to be "surplus to requirements".
The economy won't be anything like it is now. They won't need us to make stuff for them, nor will they need us to buy stuff from them. They will control, and therefor own, everything: all of the means of production, all of the resources, and all of the power.
They will have extracted all of the value from us that they possibly can. Beyond having a few human playthings and other assorted slaves, they won't need us for anything. We'll just be a useless drain on resources and an unwanted contributor to greenhouse gas emissions. Either we'll be worked until we all die, or we'll simply be exterminated.
Things could play out differently. But if anyone has any logical, compelling arguments to counter the extremely dystopian one I just posed, I would sincerely love to hear them.