> In the first society, the probability of the artist completing and selling that masterpiece is correspondingly lower, since money is a strong motivator and even artists have bills to pay.

I live near the (supposedly) largest art market in the USA, and I know a large number of artists here for whom two things are true:

1. they cannot make a living from just their art. 2. they will create art whether they make a living from or not.

Thus, the claim that taxes on their art income act as a disincentive to create just holds zero water for me. In fact, less than zero. It betrays a fundamental lack of understanding of why all the artists I admire actually do what they do.

This also applies to most of the people I admire in almost every field. I don't know of any example where the motivation was such that increased taxation would have acted as a disincentive. That's true even for Bezos @ amzn.