NOTAM could be run from a pre-historic Toshiba mainframe. it's static. Doesn't need billions in funding.
Once that happens, you have to hope that your backups work - why bother having disaster recovery drills for a static system?
Once you realize that your backups are hosed, you may experience a creeping suspicion that software is never truly static when human operators are involved.
I would not be surprised to learn that this was the case here, too.