What were the steps taken (in the study) to make the original forecast? In other words how sceintific was the original estimate?

I think that is very important when judging the response to negative feedback. If you pull a number out of your hat and then ignore some short-term feedback that’s one thing.

If you have a good estimate process and are undeterred by some bumps in the road that’s quite another.

But there’s no denying that business people get trapped by “sunk costs” and that they religiously ignore disconfirming evidence.