> The researchers quoted in the article are, essentially, defining collusion as knowing what competitors prices are.

It really is just another display about how injured the concept of "collusion" always was. Plenty of competitors have met in smokey rooms in order to fix prices, but you don't actually have to speak to each other to agree that if all of you can maximize your profits together, you should. Everybody knows how much everybody else is charging.

The ideal competition myth only works in a fictional zero-cost startup, zero-cost supplier, zero-cost distribution scenario. In real life if you try to enter a market with a few competitors with super high margins, they'll just threaten to freeze anybody who buys from you or sells to you out of the market, then offer you a ticket into their cartel.

Doesn't make it not evil, though, and it doesn't mean it's not an essential function of government to stop it. Government can't allow powerful little subgovernments to build up. You might as well allow paramilitary militias.