"Stock bubbles could be avoided by restricting how much money can be invested in stocks, on an annual basis, to keep the price earnings ratios around 15."
Err...what? Who decided 15 was the ideal? What about those companies that clearly don't deserve that multiple based on their growth prospects, or companies that clearly deserve more? Why bother with a market at all?
He asserts that it's not socialism, but I'm having a hard time seeing how it wouldn't be worse.