The history of Southwest Airlines' destruction from within
old.reddit.com
old.reddit.com
I'm just making things up, but this seems like a way to position the phone system as a bottleneck.
The article addressed this, imho.
1. Software from the 90s was neglected (cost center that didn’t improve roi, with roi being a focus of the new CEO from 2004).
2. The software didn’t grow with the airline or contemporary circumstances that the front line people were aware of a notified the management of multiple times to no avail.
Edit:
This answers your question somewhat:
https://www.reddit.com/r/SouthwestAirlines/comments/zxg6op/t...
The tl;dr is that the airline had grown but the processes were still largely manual rather than automated with a small enough margin of error that a bad storm might cause the system to collapse.