Don't forget that in the Forties Fifties and Sixties Britain's two airlines were nationalised, and the wartime culture of government control over aviation was still visible. Airliners were designed for our colonial routes, sometimes making them over-engineered for the really dense profitable routes. While Comet 4s departed Heathrow at a huge climb angle, the early 707s just about scraped over the fence, because Boeing didn't have to design for hot-and-high colonial routes.
Governments are generally very bad at running aviation.