Just end Social Security already. Let people keep that money in their paychecks. I'm sure the smart ones will invest wisely, the stupid ones will work until they are 79 or until they drop dead. What better incentive to quit the shitty jobs and work harder to make yourself more successful than by removing that safety net for poor people.
Bootstraps people, bootstraps.
In theory yes, people would just work till 79.
In practice, people on SSI aren't working (that's why they're on SSI).
You'd see
1) worse homelessness and crime as a result of the loss of income and government support
2) more use of hospitals as shelters for the homeless at tremendous costs
3) food insecurity for elders and the disabled
4) increased general healthcare spending across the board (there's a phrase that says an ounce of prevention is worth a pound of cure. Its very much true when it comes to healthcare expenditures. However if people can't afford that ounce of prevention...)
We are the richest country in the world. Yet we can't figure out how to take care of our sick, disabled, children, and elderly when relatively poorer civilized countries have basically figured it out? Look at homelessness rates in S. Korea (its near zero). Why? Really interesting anti-homelessness policies is why.