> making the creation of billionaires a policy goal

Concentrating wealth to the degree of the US is not at all necessary for innovation. As an extreme example, Bezos would have done the same thing for a tenth or less of the current lifetime income.

In fact, when many leading entrepeneurs started, the wealth concentration wasn't nearly as high, yet they were still motivated. Now with wealth concentration much higher, my impression is less motivation and opportunity for startups, innovation, starting a business in your garage, etc. In more economic terms, I think it's well-established that such high concentration of wealth reduces economic mobility.

The causation is in the other direction. Innovative entrepreneurs cause wealth to become highly concentrated, and cause their companies to distort the societies they're embedded in, by the act of producing goods and services that a large number of people want to buy.

Bezos is actually a great example, because he made almost his entire US$250B fortune from unrealized stock appreciation rather than salary or new awards. Even the most extreme wealth tax proposals I've seen wouldn't get him down to US$25B. The US could only have achieved that target by restricting how much Amazon is allowed to innovate and grow.