What makes software so hard?

Great article in the August issue of The Rational Edge, "What makes software so hard?". I have been convinced for some time that software is a design and not a manufacturing process. The article clearly describes the difference in explaining where in each type of process lie -

"On the other hand, for software projects, the relationship between
architecture and design versus production is not only inverted, but in
fact approaches infinity: since the production or manufacturing costs
for software are almost nil, almost all cost for a software
project comes from the workflows dealing with the creative parts --
that is, the invention and design of software."

Another great quote is the author's comparison of software to writing a novel. The metaphor fits so well -

"In a sense, creating software is far more closely related to writing a novel than to any traditional engineering effort -- an author is free to construct whatever type of story, limited only by his imagination and whatever facts may be necessary to the narrative. Furthermore, the author must construct the architecture of the story in his head, and to make sure the design and implementation of the story is consistent with the overall architecture. The quality of the author's product is to a high degree based on whether he succeeds in keeping the details of the story consistent with the architecture."

It is the notion that software is like manufacuring that has really turned me against big process improvement efforts like CMMi that are pushed from the top down. Anyone in a corporate environment has likely lived through at least one such effort. They usually seem so to be attempts to create predictability that does not exist in software and turn developers into interchangeable pieces that can be shuffled around a Gantt chart.