The extraordinary evidence is the proof of collusion - which we have. That's all that it takes to corrode away the basic tenants of a free market, and it's why collusion is policed the way it is. It is, frankly, a mistake to play down the impact that collusion between landlords has on the rental market.

"When competitors agree to fix prices, limit production, or engage in other forms of collusion, the natural balance of supply and demand is disrupted. This disruption typically results in higher prices for consumers, as the competitive pressure that usually drives prices down is absent."

"Collusive practices can also lead to a misallocation of resources, as they distort market signals that guide investment decisions. In a competitive market, prices signal where resources should be allocated to meet consumer demand most efficiently. When prices are artificially set through collusion, these signals are corrupted, leading to resources being channeled into less productive or less needed areas."

https://accountinginsights.org/collusion-in-markets-detectio...