Those employees could, if not see this coming, at least knew the system was antiquated and brittle. A failure of some magnitude was inevitable. This failure however was so bad that they lost everything. They didn’t know where their own planes were, where their crew was, where baggage was, anything. It was all lost or at least inaccessible for days. The details of how and why the failure happened I am sure will come out, but essentially this was tech debt that the previous CEO saw no value in improving.