If you mean the airlines when you say customers, I would say you are correct. Planes are flying slower these days because it saves fuel and one can offer a lower fare. If you mean the people who fly, when you say customers, I would say that is incorrect. People have no idea that flights can have different lengths and the only way to search for fares is by destination, number of stops, and price. It would be great if airline ticket buyers had search parameters for leg room and flight time so that those very important parameters could be selected for. Otherwise evolution will continue to force slow flights and smaller seats.