Why did Vista take seven years?

moishelettvin.blogspot.com — The most frustrating year of those seven was the year I spent working on Windows Vista, which was called Longhorn at the time. I spent a full year working on a feature which should've been designed, implemented and tested in a week. To my happy surprise (where "happy" is the freude in schadenfreude), Joel Spolsky wrote an article about my feature.