That is a rather trivial analysis that assumes a system where everyone, regardless of income, got $12k more than they would otherwise. It would be easy to set

That is a rather trivial analysis that assumes a system where everyone, regardless of income, got $12k more than they would otherwise. It would be easy to set a tax system such that people got $12k as a minimum, but those who earned (say) $20k received $6k and by $50k there was no increase. I'm not suggesting a curve with those figures, that is purely for an example.