So I have read, this is arguably what Piketty's book "Capital in the 21st Century" indicates.How Capitalism Is Dying
tl;dr: people earn money faster through investment than labour. Therefore overall the richer people are the proportionally faster they earn and wealth accumulates in fewer and fewer people. Eventually they can effectively only earn by increasingly directing more income towards themselves (e.g. often via rent), and use their wealth to capture the government to do so. Eventually they screw everyone else to the point that there's a revolution and lots of their amassed wealth is burnt down in an orgy of destruction and forcibly redistributed. Then the process cycles round again.
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So I read somewhere, apparently once you remove tech firms, US economic growth is anaemic to non-existent. But tech firms have effectively become mass rentiers, squatting on systems that effectively allow them to gouge everyone else. Apple gatekeeps access to its phones such that 30% of what is paid for apps drops into its pocket... just because it owns the only means to provide apps. Amazon is even worse: 50%, and so much market dominance its effect is arguably to increase online retail prices. Together, Google and Facebook are effectively gouging eyewatering sums from advertisers because of so much control over platforms with advertising, and so on. No wonder the USA wants TikTok: whoever owns these massive online platforms gets to gouge the world.