>It’s also why major states like Japan, China and Russia have for the most part failed to build a competitive airliner against the duopoly.
I don't think that has anything to do with it at all. Building a competitive large airliner requires a huge industrial base. And since it's so safety-critical, it takes a lot of time and expertise to build the reputation needed to unseat the incumbents. China has an aircraft manufacturer, but time will tell if it goes anywhere, since they don't exactly have a reputation for high quality. Russia has built many large aircraft in their Soviet days, but their industrial base has eroded so they probably just don't have the capacity to build competitively-priced aircraft in volume now, plus they're not well-liked by most countries that would want airliners anyway. Japan might be able to do it, but just isn't geared up for building lots of large aircraft so it would be a huge investment to build such an industry almost from scratch.
Fuel efficiency isn't a factor because building an airliner doesn't involve building engines for that airliner, and engines determine an aircraft's fuel economy for the most part. Boeing and Airbus don't make jet engines: those are all made by Rolls-Royce, Pratt & Whitney, and GE.
I don't think that has anything to do with it at all. Building a competitive large airliner requires a huge industrial base. And since it's so safety-critical, it takes a lot of time and expertise to build the reputation needed to unseat the incumbents. China has an aircraft manufacturer, but time will tell if it goes anywhere, since they don't exactly have a reputation for high quality. Russia has built many large aircraft in their Soviet days, but their industrial base has eroded so they probably just don't have the capacity to build competitively-priced aircraft in volume now, plus they're not well-liked by most countries that would want airliners anyway. Japan might be able to do it, but just isn't geared up for building lots of large aircraft so it would be a huge investment to build such an industry almost from scratch.
Fuel efficiency isn't a factor because building an airliner doesn't involve building engines for that airliner, and engines determine an aircraft's fuel economy for the most part. Boeing and Airbus don't make jet engines: those are all made by Rolls-Royce, Pratt & Whitney, and GE.