I think Thomas Piketty has provided a useful metric for this discussion: r>g
When the rate of returns on economic investments exceed the rate of growth of the economy, that's the point at which capitalism guarantees rising wealth inequality.
(Of course, I could be wrong about that, too)
"Piketty shows that modern economic growth and the diffusion of knowledge have allowed us to avoid inequalities on the apocalyptic scale predicted by Karl Marx.
"But we have not modified the deep structures of capital and inequality as much as we thought in the optimistic decades following World War II.
"The main driver of inequality—the tendency of returns on capital to exceed the rate of economic growth—today threatens to generate extreme inequalities that stir discontent and undermine democratic values.
"But economic trends are not acts of God.
"Political action has curbed dangerous inequalities in the past, Piketty says, and may do so again."
Capital in the Twenty-First Century ? Thomas Piketty | Harvard University Press
Free markets ensure rising inequality. Piketty notes the difference of those who own wealth and those who only own their labor. Corporations (defined by their unlimited treasury to influence the political process in their favor) in one for or another will always arise from free market system. As folks gain wealth, naturally they desire to influence the political, social, and economic for their security. All free market models operate this way. So it definitely ensures rising inequality indefinitely. Given the profit motive, no one would not use their wealth to secure their wealth and expand their wealth, using whatever means necessary. Piketty says free markets are great at producing new wealth and that's evident.
Past a certain threshold, all free market models end up collapsing or needing massive regulation--becoming incompatible with meritocratic values. Piketty argues for the latter of regulation to balance the un-meritocratic and unequal distribution.
Krugman seems to interpret Piketty in a way that implies meritocracy is giving way to family dynasties in the US:
"In America in particular the share of national income going to the top one percent has followed a great U-shaped arc.
"Before World War I the one percent received around a fifth of total income in both Britain and the United States.
"By 1950 that share had been cut by more than half.
"But since 1980 the one percent has seen its income share surge again—and in the United States it’s back to what it was a century ago.
"Still, todayÂ’s economic elite is very different from that of the nineteenth century, isnÂ’t it?
"Back then, great wealth tended to be inherited; arenÂ’t todayÂ’s economic elite people who earned their position?
"Well, Piketty tells us that this isnÂ’t as true as you think, and that in any case this state of affairs may prove no more durable than the middle-class society that flourished for a generation after World War II.
"The big idea of Capital in the Twenty-First Century is that we havenÂ’t just gone back to nineteenth-century levels of income inequality, weÂ’re also on a path back to 'patrimonial capitalism,' in which the commanding heights of the economy are controlled not by talented individuals but by family dynasties."
Why We?re in a New Gilded Age by Paul Krugman | The New York Review of Books