Huge income disparity ensures a complete slowing down of social mobility. The rich don't see the price we all pay. Nor do they care about the returns made on the investments that the state makes in its citizens. The state that provided my education and housing for a period of five years enabled me then to work and pay taxes for the rest of my life. Without that support I would not have been able to work and support my children as I always have. Mobility for me came from access to education, housing and childcare. It was that simple. The super-rich, however, may bypass the state altogether and, as is now clear, exist beyond the reach of government. They are untouchable.
Social mobility is fine in theory, but in practice we live in a society where it is becoming more and more difficult for many to move at all. Nudging is not nearly enough. The reality of deepening inequality is horrible paralysis. The numbing of chance is never a fine thing.