There are a number of practical problems with the proposal.
(A) At present there is now or very soon to be NO “excess” FICA revenue that could be diverted from paying current retires, because SS is now or pretty near the point of starting to NEED to cash in the IOUs the treasury gave it when “excess” FICA revenue was given over to general federal expenditures. There is no immediate remedy to that than some cobination of, (a) higher FICA taxes, (b) adjustments to SS retirement age(s), (c) adjustments to SS benefit cAlculations for newer retirees, (d) adjustments to calculation of taxable SS benefits with the taxes on SS going back into the SS fund instead of the treasury, and (f) specific new federal taxes legislatively/legally restricted to going only into the SS Fund.
Once we get past all that.
(B) There should be no federal SS “index” or investment fund of any kind. Instead the working persons FICA taxes would go into a priavte account with private investment outfits of their choice, and always be the property of the individual on behalf of whom the FICA taxes were collected. The private investment outifits would have to devise accounts that could not be collected from until the “SS retiremnent age”. The inifividual would be allowed to convert their account at retirement to an annuity, or a “money purchase” pension benefit invesment account where (a) the value in the account represents that value that could fund an income, (b) a mortality factor is determined for expected lifetime of the indivual, and (c) the type of pension account deasired (totally fixed - Bonds and treasuries, index funds, high dividend earning investments, or others suitable to the individual’c choise) and (d) from A with B and for C a monthly starting benefit amount can be determined, and may change over time as the valuation of their chosen underlying account changes.
But getting from A to B is not going to be painless, financially or politically, because the existing sums in IOUs owed to SS are just too huge.
extend the SS to upper earners if need be....
they always want the regular people to work longer but those govt employees whistling in the wind when they get to retire very early....
no cuts in SS or Medicare until govt employees feel the pinch...their pensions are our taxes afterall..