Others have better written about this but it bears repeating that most people will not attain the Market “average”, principally because it is a time dependent average not a mathematical one.
Take notice of this recent article by a site advocating FIRE (Financial Independence – Retire Early). Using this calculator the historical return of the S&P500 from June 1950 to June 2019 is in excess of 11% annually with dividends reinvested.
Most of us however do not have 70 years to save and invest and are driven by emotions. Also the trend is not linear but consists of wildly divergent swings including many bull and bear markets.
Average Stock Market Returns Aren’t Average helps explain this more cogently.
In fact if an 11% return were the norm why would CALPERS, the nation’s largest pension plan, have a current and near term target rate just below 7%?
It is worth mentioning that there have been times when stocks and bonds have both been in bear markets. It pays to be prudent and skeptical of grandiose assertions even with cheery little caveats that make it sound easy.