Duopolies are not just as bad as a monopoly. Duopolies might not create perfect competition, but it normally produces pretty good competition. AMD/Intel, Visa/

Duopolies are not just as bad as a monopoly. Duopolies might not create perfect competition, but it normally produces pretty good competition. AMD/Intel, Visa/Mastercard, Airbus/Boeing, etc. all have stiff competition. And your local telecom and cable company are engaged in pretty stiff competition. At least Verizon and Comcast are where I'm at.