If we assume that the 1930s were an anomaly and begin our sample in 1942, then there were only 11 down years out of 58. Stocks fell, then, in 19 percent of the years. Between 1926 and 1941, there were nine down years out of 16, so stocks fell in 56 percent of the years. The question is whether times have changed, and I think they have. The world is a different place from what it was in the 20s, 30s and 40s, and even very different from the 1960s and 70s.
Bad things happen to good stock markets.
I seriously doubt it. Technology has changed the U.S. economy for the better. We produce better goods more cheaply. Productivity rises, risk declines and the value of assets soars. No, it won t go on forever only until the market is fully valued.