Re: Will the 737 MAX ever be safe?
Moving to Airbus is a big commitment for an airline, though. Not only do they need trained pilots (and fully type-qualified, not just a quick iPad update), they also need ground crews that are familiar with the aircraft. They need maintenance crews who know the different procedures. They need a comprehensive parts store for the different manufacturer's components. They need bigger lifts to raise mechanics up to the higher engines. They need taller steps to get passengers on and off. It's a step-change in infrastructure at the back end.
Largely these are one-time costs. Higher steps will cost slightly more at each replacement, for example, but the rest are swapping out one Boeing cost for one Airbus cost. Still, airlines are not keen on making these changes, and I expect that many will just carry on as usual with Boeing unless the passengers vote with their feet. Many won't.
And for the poster above who suggested backing out the engines to the previous models and fixing the aerodynamics accordingly, airlines pay for fuel for every mile they travel. The moment your plane costs more in *fuel* that the competitor's is the moment your customers dry up.
Boeing are committed to a race with Airbus such that they can't back out of the 737 MAX. They need to get it running, and they need to have another team in the background designing the next generation of craft in this size and preparing it for production, because the wheels are clearly coming off the 737 model nowadays. Boeing need to see the MAX as a stop-gap until that new model is in production.