I agree there is no guarantee, but I'd rather bet on the market than on the government. If my wife's and my own SS contributions had been invested in the S & P 500 over the last 15 years, I'd have enough money now even with the recent market drop to more than pay for an annuity to give me double or triple my expected SS check in 2032.
Third, counteracting your scenario where you die before 67, is the scenario where you fritter away your investment and have nothing under the private scenario and live a long life.
Well, if you want protection against your own poor choices, you could move to Cuba and get free healthcare too. TANSTAAFL.
You cannot separate government/political system from the market. The stable/productive market is a product of stable and rational system of government. And we do not know what will be in 2032 - extrapolations rarely work in the historical process over long periods.