Microsoft's idea was very different from what Brooks describes in his book.

Microsoft approach was more about having senior programmers telling juniors what and how to do their job, aka micromanagement.

Brooks is about having programmers actually coding (and documenting), and have other people handling and other important tasks such as clerical non-programming tasks, developing tools, language research, version management, doing adversarial testing, helping with documentation, etc. Some of the tasks he describe are obsolete these days, but the book is from the early 70s.

According to him, doing that "relieves programmers of clerical chores, systematizes and ensures proper performance of those oft neglected chores, and enhances the team's most valuable asset — its work-product".