Economic evolution and economic inequality

The stretch between the poor and the rich is itself a cost to the economy. Richard Wilkinson's talk on TED.

Will economies, as part of their evolution, develop entities regulating efficiently the reduction of this divide?

In theory this should happen because the inequality and large divide is a cost to all sectors of income. So the affluent minority has it in their interest not to drive the divide too big while having a drive to increase their personal opulence that becomes the affluence. So philanthropy is one mechanism. Though can it cause enough of reform? Progressive taxation another. Reduced entry to means of production another(Open Source Ecology, Free Patents, FOSS electronics, Kahn education). End poverty drive another.

Robert Nozick talks of the increase of the middle classes in free trade economies. Echoing the same idea.

Mutual self-interest seems to be there to serve the mechanism of reduction of inequality.