Here's how it works:
Money was taken away from you for 47 years. It wasn't invested on your behalf, and they didn't "set it aside" for you either. They just took money from you. And they gave to to other, older people.
Today, you receive money from Social Security. The money you receive today was taken from people's paychecks last month. (I'm not saying that's wrong or unfair, I'm just citing where the government gets money.)
Meanwhile, money is still being taken from you ($140/month) and the government is giving that money to people on Medicare. Supplemental insurance too.
It's always the way: Government takes your money and gives it to the people the government wants to give it to.
In a market system, the government would have gotten out of the way, not taken your money for 47 years, and then you might have invested that money yourself to pay for the living expenses you now incur.
The government social spending (including Social Security) gets in the way of that actual solution.
There is no talking to the “I paid in, where’s my lock box” SS and Medicare crowd. Apparently there’s a standard procedure for that first Medicare office visit that involved deadening the math circuits of the brain.