From the Abstract:
Have the idle rich replaced the working rich at the top of the U.S. income distribution? Using tax data linking 11 million firms to their owners, this paper finds that entrepreneurs who actively manage their firms are key for top income inequality. Most top income is non-wage income, a primary source of which is private business profit. These profits accrue to working-age owners of closely-held, mid-market firms in skill-intensive industries. Private business profit falls by three-quarters after owner retirement or premature death. Classifying three-quarters of private business profit as human capital income, we find that most top earners are working rich: they derive most of their income from human capital, not physical or financial capital. The human capital income of private business owners exceeds top wage income and top public equity income. Growth in private business profit is explained by both rising productivity and a rising share of value added accruing to owners.True enough I suspect but perhaps past the point. In the 1950s-70s, even into the eighties, the left in the US and Europe were exercised about the "unearned" wealth of trust funders and they assumed everyone rich was a trust funders. It wasn't true then and it isn't true now. The great majority of the rich are wealthy because of decisions, behaviors and hard work on their part. It is a small minority who live of the trust funds of their ancestors. But the time for focusing the argument solely on that small minority of trust-funders has passed.
Unfortunately we have entered late-stage neo-marxism where facts no longer matter. It is sufficient for someone to earn more than another. It doesn't matter if they earned their good fortune. "Excessive" wealth is now a sin to expatiated by giving up possessions to those who want wealth without having to work for it. Trust-fund or hard-earned income - the new position is - "Gimme."