Oh wait that is actually how architects work. In fact at my work we have multiple CAD designers(not architects though) and it's not uncommon for them to completely throw away a design and start over. I think code should be mostly the same.
Of course, but the Apollo 11 lunar lander was created without the aid of ubiquitous desktop computers. I imagine the SpaceX guidance/control software was written in a way that less resembles bridge-building/Apollo 11 lunar landers and more like the organic processes we see elsewhere in the software industry.
If Neo were to build a bridge in the Matrix, chances are his processes would bear little resemblance to those of the Army Corp of Engineers.
For the guidance/control systems, I bet you're wrong.
Software is a design practice/process. Not a building process. Any analogy should be to the design phase of other engineering disciplines.
The CAD designers absolutely test if things work. Why do you think almost every engineering bureau has 3D printers.
Sure, but it is not the only one. You are allowed to think at other levels, and it can be quite useful, especially on larger systems.