> Progressive (when used in the context of taxes), does not mean this. It means that contribution increases progressively with income.

That is the same thing once you account for where the tax money goes, which it is unreasonable not to do.

For example, if you have a 25% tax that pays for a $10,000 UBI, there is a single marginal rate but the tax system is progressive because the effective rate is a curve. Someone at $20,000 pays $5000 and receives $10,000, net $5000, an effective tax rate of -25%. The effective tax rate is 5% at $50,000, 12.5% at $80,000, increasing asymptotically to 25% with higher incomes.

Compare this with a version of social security that charged higher marginal rates for higher income people, but all benefits are still paid out in proportion to what each person paid in multiplied by their lifespan. There is nothing progressive about this -- if everyone lived the same amount of time it would be exactly breakeven, and since in practice the rich live longer it thereby becomes regressive.

Counting in lifespans is pretty senseless though. If your beef is with that then it would be much more effective to charge women more for social security than men. Smokers should get a social security discount along with obese people. Use actuarial tables from life insurance companies if you want it to be fair based on what people are expected to get out of it. Finally, the rich don’t really outlive the middle class by enough of a factor to matter (especially compared to the ones above).