The National Academies of Sciences, Engineering and Medicine has issued The Growing Gap In Life Expectancy By Income: Implications For Federal Programs And Policy Responses. It's well known that persons with higher incomes live longer than those with low incomes. As an example, for those born in 1960, life expectancy at age 50 was 28.3 years for those in the lowest 20% of income but 41.9 years for those in the highest 20% of income. Naturally, if you live longer, you're going to receive more Social Security and Medicare benefits. The effect of this is that the value at age 50 of those benefits for males was $391,000 for those in the lowest 20% of earnings but $522,000 for those in the highest 20% of earnings. For females, the comparable numbers were somewhat less dramatic, $452,000 for those in the lowest 20% of earnings and $480,000 for those in the highest 20% of earnings.
It would be possible to correct this bias in favor of persons with high incomes by reducing their Social Security benefits but that's unlikely to happen. The other possible way would be to increase benefits for lower income people. I'd say that while that's unlikely, it's not out of the question. Populist campaigns seem to be in vogue this campaign season.