Earlier quoted context omitted.
There is a different perspective on that from large acquisitions around firm fixed price contracts. If you're doing some low risk building, say a 10 mile road on flat ground with known soil, replacing a previous road, that is well-known to current specs with set-in-stone requirements (no pun intended) it is easy to pitch that firm fixed price because the contractor will know exactly what to do, and there are 20 road…
You can't even get your plumber to tell you how much it's going to cost to get your toilet working smoothly again. And you want to get to the moon on a fixed budget? (Which will also require a toilet). Software has the same problems. An unreasonable expectation of being able to predict the future (except the bits they don't want you to know about), and a lot of whining when we run into unexpected issues.
Didn't last time
https://www.nbcnews.com/sciencemain/poop-space-revisited-apo...