It also means that they have competition: airlines are not fond of having to recertify their pilots and "flys like any old 737" was Boeing's main advantage over

It also means that they have competition: airlines are not fond of having to recertify their pilots and "flys like any old 737" was Boeing's main advantage over less outdated Airbus designs. Doing the engine replacement the right way would have created a pilot recertification requirement and thus canceled that advantage, no matter how much money Boeing threw at it. As much as I enjoy a good game of MBA-blaming, "fake it till you break it" is more than simple cost-cutting here. There's just as much engineering hybris at play when "can we do it? yes!" is heard while "should we do it? no" is hardly ever thought (same with diesel and urea tank refills). I see the problem more in institutionalized optimism than in penny-pinching.