Cost probably would depend on the 'moat', i.e. how easy is it for another player to enter the market.
On the other hand, we may get a kind of OPEC of asteroid miners.
On the other hand, we may get a kind of OPEC of asteroid miners.
Someone might even do it as a charity operation.
For every government supporting cartels there will be a dozen trying to break them, because of how much money you can make by breaking a cartel.
Greed still wins, for the betterment of humans.