(IMO / 2 cents) because as a software developer, you can create a huge amount of functionality in a short amount of time if you cut some corners. This just isn't the case, doesn't have nearly the fast return-on-investment that you get in other fields of engineering.

I mean in electrical engineering, idea-to-working-prototype involves a lot of design and assembly first. In structural engineering, you just can't build a bridge on your own. It goes on.

While in software development, I can cough up ten distinct features in a day if not more without forward design or testing.