The point really is to think about what the solution is. A substation went down. So, have redundant power substations? Well that had that. And a result of which, following the fire, they were able to restore power, running on the two substations that remain.
The problem is that when the power went down, their systems shutdown and rerouting took time. So, what would be needed is redundancy that can switch in milliseconds, or you will have to reboot. And even then, what happens if the backups get taken out. That happened with this event also.
That isn't reasonable. It makes much more sense to use the normal procedures for a closed airport. That happens routinely anyway. It makes no sense to spend money to prevent an airport closing for a day due to a once in an life time fire, when it closes down two or three times a year due to fog.