Sealed auctions introduce inefficiencies in capital allocation. The parties writing the laws benefit from these inefficiencies, hence market's move to transparency is written up as collusion.
Switch to open auctions would remove incentives for corruption.
There will always be incentives for corruption. For instance, your money is not flowing to me at the moment, which I find to be highly inefficient.
Giving me all your money would remove the incentive to rob you.
Also, are you seriously appealing to anarchist idealism as a justification for bid-rigging? How many of these intellectuals who are using their brainpower to rip off local governments could keep their small fortunes for more than a month in a state of anarchy? They're precisely the kind of people who benefit the most from the existence of a state, so cry me a river at the injustice of them having to play by the state's rules.
Switch to open auctions would remove incentives for corruption.