They will only become a $Trillionaire this way if they act like OPEC and control access and earth delivery of the precious metals. Otherwise they will create a glut in supply and undercut the enrichment of their own new found riches. They have to trickle out the additional supply so that it enters earth markets without depressing earth prices.
Then comes the question world courts - sovereign and international - will be asked to step into - can individuals or companies claim ownership, sole possession of, or sole rights to, objects in space. I would suggest “why not”?, but then I am not a judge of the Liberal activist or international globalist persuasion.
I’m sure anybody that has the means already knows that this would depress prices. So they withhold it, and use it as leverage and collateral..............