The problem with this post is that you are assuming the US economy will be as productive as the past 30 years. There is a real probable change that as global competition rises in productive areas, e.g., manufacturing, technology, etc. The US share of global market contribution decreases. The S&P500 has a decent portion of companies that rely on economic rent to generate profit and increase share price. Whether you like it or not, the us relies not only on citizens becoming educated enough to produce wealth through knowledge, but also from importing a lot of the brain power from other countries. Just pay attention to the trends. I do think S&P500 will increase as we are a productive country, though it's arguable that we will see the same magnitude of increase as we've seen in the last 30 years..