The biggest problem is the backward compatibility with the current system. Negative income tax with a government backed efficient job market where to overhead

The biggest problem is the backward compatibility with the current system. Negative income tax with a government backed efficient job market where to overhead of hiring someone for 2h is minimal. As a result, someone working 20h a week would have the same quality of life as someone working 40h today for a minimum wage. Worker can spend the extra 20h on education, leisure or more work. I don't think anything other would fly pocitally.