It sounds quite plausible. Almost all equity ETFs do their balancing against dark pools or directly with market makers to avoid arbitrage and to ensure enough

It sounds quite plausible. Almost all equity ETFs do their balancing against dark pools or directly with market makers to avoid arbitrage and to ensure enough liquidity. Since index ETFs have more AUM than the underlying instruments (the “ETF tail wagging the dog”), this sounds like a natural evolution. There is nothing nefarious about this, it’s just how the markets work.