In regulated capitalism, the government would step in to prevent this type of price fixing.
like this?
https://www.nytimes.com/2024/01/23/us/yale-columbia-price-fixing-settlement.html
https://www.texastribune.org/2024/01/19/rice-university-price-fixing-lawsuit/
This is like saying that Texas doesn't regulate abortion because it's just private citizens filing lawsuits. That is bullshit.
Without the regulations, there would be no legal basis for filing a lawsuit.