>Variation in wealth can be a sign of variation in productivity. (In a society of one, they're identical.) And that is almost certainly a good thing: if your society has no variation in productivity, it's probably not because everyone is Thomas Edison. It's probably because you have no Thomas Edisons.
>In a low-tech society you don't see much variation in productivity. If you have a tribe of nomads collecting sticks for a fire, how much more productive is the best stick gatherer going to be than the worst? A factor of two? Whereas when you hand people a complex tool like a computer, the variation in what they can do with it is enormous.
Now, the middle-class and upper-middle-class do subsidize the wealthiest Americans as a result of the US’s tax structure, and that’s a problem. But aside from that, the fact that the top quantiles in the US are wealthier than their equivalents elsewhere is not fundamentally a bad thing.