> That's almost a tautology then.

No... it's not? Do you know what tautology means?

> If you only know one thing about someone, that's also necessarily the best predictor for anything about them.

Except it's not the only thing you know about them... so your point is kinda meaningless.

> However, it doesn't tell us much about whether wealth does concentrate over time.

There are soooo many studies supporting this, like the two I linked above, not to mention common sense.

It's like the most basic game theory + common sense - you have X people competing with each other, you give (0.001 * X) of those people massive advantages - who do you think is going to be winning?