The biggest limiting factor in airplanes is the production speed. Building airliners is slow which is why there are very long waiting lists. Nothing’s wrong that’s just planes. New planes are cheaper to operate so its a good idea to order new planes even if you’re not planning a significant expansion.
This is also why airlines will be slow to react to boeing’s safety record in orders. Switching orders means losing your place and going to the back of airbus’s waiting list.
True, but this article is specifically about the 737. Apart from the a220, none of the aircraft you listed are both in production and part of the 737’s market segment.
The a320 neo family has about 7000 orders awaiting delivery. It is not feasible to switch for most airlines for the reasons I previously mentioned.