This never made sense to me. You get out of Social Security more or less what you put into it (with lower income earners actually getting a bit more, proportionately speaking). If you remove the cap, people will be paying more into it now and pumping the fund up. Eventually, we just hit the same problems when those high income earners eventually withdraw, since they’ll be pulling that much more, as well.
I get the “tax the rich” idea, but Social Security isn’t a tax, at least not in the same way as everything else. It’s a retirement fund with mandatory contributions.