The original idea was forcing people to save for retirement, providing a risk-free program, and reducing the public problem of broke old people. It was a good solution in that a lot of people really don't have much of anything saved.

The reason to give older folks their social security is that it's the return on their investment from when they were younger. Not giving it to them would break the promise. And those payments are built into people's retirement plans. You want to not pay them out, then you gotta refund all the money they put in. With interest.

And we do, btw, claw it back from rich people. We tax social security benefits (something Trump wants to eliminate) and people with higher income get taxed at a higher rate. If you're rich, your retirement income is still high as you liquidate investments for living expenses, so you're paying high tax rates on that income. Perhaps you're also living in a high-tax state. That's even more clawback.

But the real reason not to change the program is that it just pays the elderly poor, it becomes a target, just like SNAP. All the lies and machinations designed to kill the social safety net will apply to social security. And pretty soon, we'll have a program that's been trimmed and trimmed and trimmed until it is only used by our poorest and least powerful. And then some asshole will kill it off entirely because preventing people from starving looks like "waste" to people with no empathy.