This claim is often repeated but simply misleading. Taxable income is only a tiny fraction of the wealth of ultra rich folks - many even take symbolic wages, because their real compensation happens in stock, which they can use to lend effectively infinite money. There's a great episode of the Ezra Klein Show on this topic too[0].
[0]: https://open.spotify.com/episode/3Jjy4drElYHNMRtxVQPENR?si=5...