This will be great for them. What this means for Americans is rather more uncertain. Many of us will benefit. Some will lose. This is a plausible scenario.
Stock prices stay where they are for many years.
That's what happened after the 1901 peak in the market long ago. In that case, nothing particularly bad for the economy, just disappointing returns for stock market investors. He is too worried about what happened 100 years ago. If the market is flat for 20 years and earnings grow at the same rate that they have since the Second World War ended, then the price-earnings ratio for the market would be well below its long run historical average. I hold my ground that flat for 20 years is an entirely plausible scenario.