Even in areas with multiple competitors, they can (and do) effectively collude by getting their information through data brokers and third parties.
I don't have a solution, but we are currently very far away from a free market in general.
“It was supposed that the pearl buyers were individuals acting alone, bidding against one another for the pearls the fishermen brought in. And once it had been so. But this was a wasteful method, for often, in the excitement of bidding for a fine pearl, too great a price had been paid to the fisherman. This was extravagant and not to be countenanced. Now there was only one pearl buyer with many hands"
I get about a dozen fliers in the mail every week advertising deals that are surely loss leaders for the grocer. Then there's extreme couponing forums.
Have you worked in a large organization? I can't imagine it's easy to coordinate much less have someone make actual decisions.
The government IS preventing coordinated price setting by closing the loophole of third party data brokers.
Ok.
Can we get to what this kind of law is actually doing? The simplest version would be roughly "stores need to display prices and only change them once per day". No specific prices are being imposed.