Cruise lines are Cournot oligopolies with fixed supply, so operators hold pricing power and earn monopoly-like profits.
Construction equipment rental is a Cournot oligopoly with inelastic demand, supporting durable high returns.
Nicotine creates the strongest secondary reinforcers, so cigarette and vaping brands earn the highest margins and loyalty.
Carvana is the most efficient used-car retailer with widening moats, and margins still climbing toward 13-14%.