The "invisible hand of the free market" works only, if you have many market participants competing one against another. When a participant wins the competition you get monopoly, when multiple participants collude you get oligopoly, or cartel. Market can not solve this.

Historical examples:

https://en.wikipedia.org/wiki/Standard_Oil

https://en.wikipedia.org/wiki/Phoebus_cartel

https://en.wikipedia.org/wiki/DRAM_price_fixing_scandal

https://en.wikipedia.org/wiki/High-Tech_Employee_Antitrust_L...

https://en.wikipedia.org/wiki/OPEC