"Have you looked at a chart of the market from 1929 to 1949, or 1966 to 1992? The market does not always go up. Sideways is not a good thing, Down is not a good thing, either..."
Yep.
And in some detail, both large and small cap stocks, and including dividend returns, instead of just looking at prices.
The total return of a diversified portfolio isn't well represented by the DJIA.