>Arguably United airlines shouldn't have chosen a product they can't test updates of, though maybe there are no good options.

I used to work with regional parks and recreation departments, and they would not approve any updates that did not go through UAW environments that we had set up. All updates had to be deployed to their UAW, thoroughly tested, before going to their production environment.

I get this this is slightly different, but I'd imagine Airlines, Banks, and Hospitals would have far more strict UAW policies to avoid a single vendor from kneecapping operations.