It is almost always different people who are getting richer, owing to rotation at the top of the wealth distribution.

The claim is hedged ('almost always'). It is judged against empirical studies of mobility at the top of the wealth distribution, such as turnover of the Forbes 400 or similar rich lists, or panel data on top wealth shares. True: the studies show high turnover, with most of the people at the top or gaining wealth at the top over typical periods being new entrants rather than the same persistent individuals. Mostly true: turnover is substantial and makes up a large share of membership at the top, but there is notable persistence. Mixed: turnover and persistence are roughly balanced, or the studies disagree. Mostly false: there is some turnover, but the same individuals or families mostly persist at the top and capture most of the gains. False: the studies show little rotation at the top.

Set before the research began.

1. E1 The Wealth Elasticity of Political Contributions by the Forbes 400 Adam Bonica (Stanford University) and Howard Rosenthal (New York University), working paper PDF

   “In 2012, only exactly half, 200, of the 400 members ten years earlier, in 2002, were still members.”

2. E2 The Wealth Elasticity of Political Contributions by the Forbes 400 Adam Bonica (Stanford University) and Howard Rosenthal (New York University), working paper PDF

   “but relatively young new entrepreneurial blood (Bill Gates, Mark Zuckerberg, Michael Bloomberg, George Soros, Larry Ellison) is constantly entering.”

3. E3 SPECIAL Tax Foundation (William McBride), Special Report No. 223 · July 2014

   “Of those on the 1987 Forbes 400 list, only 73 remain there in 2013.”

4. E4 Silver Spoon or Self-Made? Exploring 23 Years of Wealth Mobility Federal Reserve Bank of St. Louis, On the Economy blog (Serdar Ozkan) · 14 December 2023

   “Furthermore, 29.2% of the wealthiest households were already ranked in the top 0.1% of the wealth distribution initially in their late 20s and early 30s.”

Forbes 400 data show substantial turnover: only 73 of the 1987 list remained in 2013 (E3), and new entrepreneurs are described as constantly entering the list (E2). Persistence is also notable: half of the 2002 members were still on the list in 2012 (E1). A Federal Reserve analysis reports that 29.2% of the wealthiest households were already in the top 0.1% of the wealth distribution in their late 20s and early 30s (E4). Turnover is large but persistence is meaningful, so the hedged 'almost always' claim fits the mostly-true criterion.