Believed by whom? Because AFAIR this was never either the general public sentiment or consistent with BLS projections across the fields that CS feeds into.
Post dotcom crash in the early 00's? Everyone was saying this was a dead market. Cost-cutting was everywhere.
The options I was weighing were philosophy, math, or CS. I chose CS because I liked building things. I figured I could at least make minimum wage. If it turned out so terrible I could just go back to school for something else.
Much to my relief, my first job out of college paid me $50k.
The hilarity is that I went into Linguistics instead, and it turns out that in 2023 that is actually very helpful... I'm not the only one either.
I do remember it being a big concern on the part of 9-to-5 coders at large corporations.
Interestingly, he enrolled in CS at a time it was believed to be a dead career, with offshoring replacing expensive American engineers.