The analysis by Andrew Leigh is of course "STATIC ANALYSIS". It assumes no change of behaviour. Or to put it differently it assumes that there will be no incentive effect.

My bet is that the government will raise more tax revenue as a result of this tax rate cut. Such a conclusion could only be demonstrated with DYNAMIC ANALYSIS. In any case I would expect that the benefit from extra tax revenue would flow rather unevenly also.

In other words who really has a clue on how the exact numbers will pan out. Any move closer to zero income tax is progress in my book.

The Melbourne Institute has done some "dynamic" analysis, as far as I know. They might be able to say whether the tax take is predicted to increase after behavioural responses to the changes.

They did do a recent comparison of the Government and Labor tax proposals (see: http://melbourneinstitute.com/publications/reports/ )

As far as zero tax goes, who would you have to pay to ensure you weren't coerced into paying tax, or its equivalent, to someone else? And would that be a tax of sorts?