I think the article misses the point on what a billionaire tax and a progressive tax system in general should be about. Tax systems in modern societies are not solely about generating income for the state but to a part also about distributing wealth more fair.
We are coming from a time where the marginal tax rates were between 70% and 90%. Now it‘s under 40%. [1] This is probably one reason why we came to the point were we have to discuss billionaires tax in the first place.
1) I think that the redistributionist view of taxation is still quite controversial (at least in the US)
2) I think redistribution via taxation is exceedingly unpopular if you are paying for it (I.e. people are all for other people paying more, but not themselves)
3) while marginal tax rates were higher previously, a) the highest marginal tax brackets were as high as $100m in today’s dollars, and 2) effective tax rates were not massively different (can’t find a source here, but recall seeing data on this) through avoidance/deductions etc. such that tax collected per dollar of income actually hasn’t changed much.
We are coming from a time where the marginal tax rates were between 70% and 90%. Now it‘s under 40%. [1] This is probably one reason why we came to the point were we have to discuss billionaires tax in the first place.
[1]https://eml.berkeley.edu/~saez/course/Labortaxes/taxableinco...