Of the two SS is by far the easiest to fix. Raise the cap on taxable income to $1M from the current $148K. Problem solved. One step further would be to means test for benefits.
No that wouldn't solve anything, unless you want to be evil.
Social Security has a cap on the taxable income, because it also has a cap on the maximum payout.
If you increase the taxable income, you MUST also increase the max Social Security payout. That would mean that Social Security expenses would dramatically increase, with the increased revenue.
So it wouldn't fix anything.
Unless you plan to have people pay more into a "pension" and yet not get any more benefits paid out.
Would you tolerate that? If your insurance company said that for no other reason than because you had more money that other people, that your insurance premiums would increase by.... 10 fold.... and yet your insurance policies would not pay out one penny more in benefits, would that work for you?
Or would you have a huge problem with that?
You would have a huge problem with that wouldn't you? And you'd start having a complete fit, until your benefits were increased to match your increased premiums.
Well... welcome to Democracy baby. You can't just screw over a huge portion of the public, and not have voters elect anyone who will fix that.