"The source said the NOTAM system is an example of aging infrastructure due for an overhaul."
The concept of "lint" a file and the concept of verifying a backup are truly ancient and coincidentally are also completely absent from the description of the problem. People that felt no need to do either 20 years ago are certainly not going to start doing it today, especially when the inevitable system failure in the distant future results in yet another lucrative replacement contract in the distant future for system 3.0.
I think you're misunderstanding what the "backup" was in this context (in particular as the article is unhelpful by calling it a backup file, which isn't accurate).
In this case it is two PRODUCTION systems running concurrently. The primary and the secondary (article calls the "backup"). Primary went down due to corruption, but the identical secondary system couldn't be switched to because the corruption also occurred there.
No, it's the RAID vs Backup distinction. If you have 2 disks in Raid 1, you have a system that can survive one drive dying (high availability), but you also need a backup system (offline).
It sounds like their high availability system failed but they probably were able to restore from backup (offline)
The concept of "lint" a file and the concept of verifying a backup are truly ancient and coincidentally are also completely absent from the description of the problem. People that felt no need to do either 20 years ago are certainly not going to start doing it today, especially when the inevitable system failure in the distant future results in yet another lucrative replacement contract in the distant future for system 3.0.