Is it best for society that everyone works a job with high enough income to contribute to taxes and that can accrue a 401k? We aren't there under current policy, there are many people left behind and experiencing negative income tax rates. But I feel this hypothetical world is the ideal posited in your example.

I think it's a fair question, and as an economist the topic fascinates me far beyond the typical econ 101 perfect world hand waving.