I've had years when I was in that 50%.

Oddly enough, a substantial amount of my income went to the Federal general funds in those years. Unless that money is really going to be paid back to the Social Security fund, in which case Social Security is doing pretty well for a very long time.

Does overpaying Social Security so rich guys don't have to pay on most of their income balance not paying in the other column? Depends who you ask, how you do the math. But "50% don't pay taxes" is not a particulalry honest statement. "50% don't pay Federal income tax except indirectly if the general fund never repays the Social Security fund" isn't as catchy, I guess.