That's why having a base of consumption rather than income as the tax base used for S/Ss would be preferable and less punitive on income earners.
People who don't have much disposable income won't do much consuming. Look at consumer debt today. People are up to their eyeballs in debt. Those same people aren't saving appropriately into their defined contribution retirement plans. They really expect social security to catch them when they retire with insufficient money set aside for retirement. Those same parties will likely still be mired in consumer debt on retirement, but they won't have a fat paycheck to cover their credit obligations. They are in for a rude awakening.