I've read the book and get your general point. However, having a hard time believing your math. Are you assuming 8% compounded annually? I have no idea how to do that.
Vanguard's Total Stock Market index fund [1] has seen an average annual return of 8.87% since inception in 1992.
[0] http://www.bankrate.com/calculators/retirement/retirement-pl...
[1] https://personal.vanguard.com/us/funds/snapshot?FundId=0085&...