> If a lot of the wealth is concentrated, the people in the middle and bottom are very squeezed in terms of what society actually offers them (generally)

I'm not sure I understand the connection though. I don't see how one party having a large amount of wealth, however defined, necessarily precludes any other party from having any amount of wealth.

> whereas if the wealth is more evenly distributed, society tends to make sure everybody's getting along well, with health care and schools and what-not.

But the underlying underlying in statements like this is that wealth originates in the aggregation, and individuals subsequently claim a portion of it, which seems counter-intuitive and false.

Particular people build things like schools and hospitals in particular places, generating wealth for the specific people involved. 'Society' doesn't ensure that people have these goods; people create these goods for themselves, and generate society in the process.