Earlier quoted context omitted.
This is a strawman. Look up how utterly fucked social security is and tell me with a straight face it is a good system and you'll get value from it.
Sure, but what replaces it? You're talking a catastrophic level of pain and suffering if there's nothing to take its place.
In principle the US could phase such a system in by redirecting future Social Security payroll taxes to 401(k)s while maintaining existing commitments. But because Social Security is so deeply underfunded, workers would need to keep up solidarity payments for decades without any expectation of reciprocity once they retire.
Still, everyone would be better off in the long run.