This ignores basic supply and demand, though. If no one can buy them, why would they make them? And if Company A is pricing them way too high or unfairly, what's to stop Company B from offering the same thing at a lower price point?
That's sorta the problem. No one can buy them, so nobody makes them. End result is that the economy stops functioning, nobody builds anything, and a perma-depression occurs. This can't be a good thing...
As for what stops company B from competing - it's the cost of tooling up all these automation centers and the risk that after all that, your "prey" may itself get better and nobody will buy your product. Microsoft was massively profitable for the 1990s. Google was massively profitable for the 2000s. Why did nobody compete with them? Because if they did, Microsoft/Google would crush them like a bug.
I guess Marshall would argue that if there were no wealth redistribution scheme, all the non-executives would simply die off, followed by all the executives who made stuff for them, until eventually only a micro-economy existed of executives making stuff for other executives.
I agree that Marshall is concentrating too much on one side of the economic equation, though. He ignores that people could form less efficient micro-economies rather than die off. He ignores that human desire is ever-changing and limitless, capable of out-stripping the most efficient production facility. And he ignores the fact that people have intrinsic value to other people apart from employment: to interact with, to command, to love. People will pay to keep other people alive and happy.
