Speaking as a guy who knows nothing about the business looking in, I’m reminded of Michael Crichton’s Airframe and one of the character’s comment “We Have To Do Business With These People.”
Jeju could jump ship to Airbus, but that’s not like nor as easy as Joe Average jumping from say a Ford to a Nissan or KIA.
Airbus could use the additional business, but has its own production backlog and engineering problems to work through.
Nor is there any other credible airframe builder offering a viable 3rd option to the Boeing-Airbus duopoly (yet) for narrow-bodies.
In a land of lousy options… shrugs
Regards