There’s only 1.8M bitcoin left on exchanges for the blackrocks of the world to try messing with. Plebs are going to keep the buy pressure up and taking that coin off exchange. Blackrock would be eventually put in a situation where it’ll be obvious their ETF isn’t backed (if they were dumb enough to not back it)..
That said, a lot of the reason for the delay in the ETF approval is the reporting side of this where SEC wants to prevent such things from happening. I have a feeling it’ll be more transparent than what many are led to believe, otherwise it’ll just fail over the long term