This is the nub of the problem when it comes to software. I understand your skepticism but software development is really very different from other activities. It is "mind-stuff" (and thus quite unstructured) which needs to be expressed in very precise language to solve an [almost always ill-defined/constantly redefined] problem. The inherent complexity involved is huge due to the number of degrees of freedom and malleability involved.

I can do no better than point you to the article "The Humble Programmer" (http://www.cs.utexas.edu/users/EWD/transcriptions/EWD03xx/EW...) written by one of the pioneers of Computer Science to really understand the issues that make Software Development such a complex and difficult activity. And since then (the article is from 70's) we have made matters exponentially worse by orders of magnitude.