Just before Easter, and (ahem) while some of us were travelling, the Brookings Institute hosted a panel on the topic, "Can retirement plans provide safe income?" for which the video and transcript are both available. The sessions featured economist Richard Thaler, known for his concept of the "nudge" and behavior economics, for which he was awarded the Nobel Memorial Prize in Economics in 2017, so he gets attention when he makes proposals, as was the case here, when he suggested that Social Security have a "buy-in option." Thaler said:
What I'm proposing is that people would be allowed to take a portion of their 401(k) benefits when they retire and send it to the SSA, up to some cap, say, 250,000 -- 100,000 actually would do a lot that's more than something like two-thirds of the current account balances in 401(k) plans, so 100,000 would do a fair amount of good.
Now what would this get you? It would get you the only indexed annuity -- so price adjusted -- that's guaranteed by the Federal Government. It would get you that at fair actuarial value. No one in the private sector is prepared to do either of those things, or as far as I know there are no indexed annuities, and certainly none guaranteed by the government.
Thaler rejected the prospect of the private sector offering annuities on a large scale, because they wouldn't be able to handle a "major change to longevity" and because consumers would then be at the mercy of " the fly by night insurance company in Mississippi" (a characterization I suspect that mainstream highly-rated insurance companies would take issue with).
As it happens, the bulk of this panel was much more technical and focused on topics such as tontines, retirement account spend-down, annuity purchases from 401(k) accounts, and so forth, rather than a detailed presentation of the specifics, but it's not the first time that someone's proposed expanding the role of Social Security in this way.