OK, but the market has never been higher than where it is at the moment. So your calculation is like looking into the rear view mirror of your car, it says nothing about where you are going.
On the other hand, interest rates are a historic lows. GDP has been in a 2% range for sometime now. S&P 500 EPS have declined 18.5% in the last 1.5 years.
Therefore, a reasonable assumption is the next ten years will be quite a bit different than the past ten years.