You may be right, but the intent of the system doesn't really matter. When SS began the tax was 1%, now it's 12.5% and benefits have been decreasing every year.
Sadly, the planners didn't anticipate just how population trends would play out, and so the initial idea -- that everyone pays 1% and then no old folks have to worry about poverty if they choose to retire -- just doesn't quite work out any longer.
The trouble is that people can't really rely on social security for (guess what?) security!
Will congress increase the payroll tax to 30%? Will it decrease social security benefits drastically? Will it fund SS out of general revenue at the expense of other programs? Will American taxpayers decide that SS is worth a middle class income tax rate of 55%?
The answer to all of these things is the same: maybe.
But that's not security. Obama has wisely advocated converting SS into a welfare program, but that hasn't gotten much traction.
The point is, with population trends doing what they are, somthing has to give. When people running for office talk aobut "saving Social Security" they are not honest about the impending outcome of obvious demographic trends. Meanwhile, all of us pay 12.5% of every paycheck into something that will probably offer us ZERO security in retirement.