One hundred years ago, Henry Ford started his efforts that culminated in the assembly line. I don't think anybody would argue the efficiencies gained by the assembly line. Around the same time, Frederick Taylor was studying workers and optimizing their actions using Scientific Management.
A hundred years of improving process to be able to better analyze costs, risks and delivery followed. Six Sigma is the latest incarnation of that. Any repeatable task can be analyzed and made better. As you make it better, you make it faster and more predictable. A Model T coming off the assembly line every five minutes.
For a hundred years, we have learned if you analyze the process, if you make more definitions, you make the problem more predictable. And for the last 30 years, this is how software has been managed. Analyze the process, define it more, and expect faster and more predictable development.
Process is just the first factor. In part two, I will continue to discuss the reasons why Agile software development scares management.