Well the reason you don't move a bridge is because it's really hard and really expensive. Just like you don't build an airplane while it's flying because it couldn't be flying if it wasn't built.
The analogies seem to just be missing the point. There's constraints, so what?
I've worked in hard science, engineering, and software. No one is omniscient, so the goals evolve and pivot during the project. That's pretty standard practice. You can't just plan and execute unless you're omniscient. Honestly, the big differences I see is that programmers spend less time at the drawing board and engineers and scientists spend much more time there because working in physical space is very costly and time consuming. But there's a lot of similarities. Programmers would be more effective if they spend more time at the drawing board and engineers would be more effective if they could hack on their tasks more cheaply (which is why sim has had such an impact for them)
