Ive often seen individuals on the left talking about how billionares shouldnt exist etc., but when probed on how that could be accomplished the answer is usually just taxes or guillotines. I dont think either is great.
What if instead, corporations were made to be unable to be sold or owned. Initially theyre made to default to popular election for their board, and after that they can set up a charter or adopt a standard one, ratified by majority vote of their employees.
Bank collapse would probably follow, how could that be remedied? Maybe match the banks invalidated stocks with bonds?
Value was making value as you put it, long before rapid trading. Speculation and arbitrage are like the first two things that develop in any economy. Any entrepreneurial grade school child trading candy, baseball cards, pogs, hotwheels, or whatever the hot new thing is has probably seen both first hand.