Massive failures in oversight and management. Airport building/management company that makes changes to the design pretty randomly, total failure in oversight mechanisms (basically, there was no review process in place which could have caught this while it was going on), as a result a building that doesn't match the original plans, doesn't conform to regulations and where in the end the actual state of what exists wasn't even known. Brought down by failing the fire safety certifications shortly before the opening, at which point the slow "figure out what happened and who to blame" process began, and then attempts to fix it. It's a glorious mess.

Even if there had been a consensus on almost-rip-and-replace immediately, it's not clear that could have been done as quickly, given the amount of preparation needed.

(As an example of the kind of changes, during the building process they decided to re-assign arrivals and departures to different floors of the building. Which in an airport has fairly fundamental consequences due to security zones etc...)