What arguments can be made to Support Oligopolies? -What happens to Collusion?

-Firms will compete in Non-Price Factors such as Quality, Accessibility and Efficient. Dynamic Efficiency can be Presented -Firms will not raise Very High Prices as this ignites Competition and Consumers may not Buy -Competitive Oligopolies can achieve Huge Efficiency. -Formal Collusion is usually Illegal, Informal Collusion is usually Temporary. One Firm can Cheat and Lower its Prices for an Advantage (First-Mover Advantage) and subsequently triggers a Price War -