If I read the Bitcoin ETF application papers correctly, in the case of a hardfork, BlackRock could choose the suitable network on behalf of their investors.

Given the growing market share for these ETFs, wouldn't this give TradFi institutions a significant influence?

Wealth Management by profession • Crypto and DeFi by passion • Generative AI art connoisseur • Humor is desired

Currently etfs have roughly ~700k bitcoin in them. The good news is at the moment they represent a tiny portion of the holders. This should limit their influence by now, but the way that number is growing it will be a concern in the future.