Yes, I think you are missing that this would not be an apples/apples comparison because one involves risk and the other does not. You can compare but you'd be comparing two scenarios without accounting for the very important element of risk. Longevity is also a factor in the comparison.

There is also more to the evaluation of SS strategy than simply future value. There's also the issue of how this strategy and consequent cash flow fits into the planning model that you build. If the deferral of SS creates liquidity constraint, you have to deal with that, and the higher income from SS could create a higher Medicare B premium too. Those are just a few of the factors.