Because you're assuming the people on the top have liquid assets needed to sustain themselves. They would need the economy to be operating and funds flowing into their accounts via their businesses/holdings.

And these investments you talk about - they'll just be even more concentration of wealth than what we see today, especially with these more advanced AI systems and robots, not needing to hire as many people for the same output.

Why would Chase loan out money to someone that doesn't have a job, because the above AI systems/robots are now doing those jobs for the capitalists?