Hm.  That very much reminds me of the movie There Will Be Blood.  And the farmers got suckered and sold their land.

Anyway, Blackrock?  They own everything.  Just go to Yahoo Finance or any other site that lists the major shareholders of any corporation that's public and 99 times out of 100 they're one of the top 3 holders of any given stock.  It's crazy.  In fact, the same names pop up every time, like Vanguard Group, State Street Corporation, etc.  Anyway.

The question OP posed is silly IMO.  It's a scenario that isn't going to happen, and it's not even an interesting hypothetical.  Unless Blackrock had some inside information along the lines of the US government intending to make an enormous purchase of bitcoin, they would have no more information about bitcoin's future performance than any of us.  Oil can be located underneath a house without the homeowners knowing it, but bitcoin?  Nah.