There's some great insight in it, though it is long. Then I got to this part:
Optimists tend to be promoted, so the higher up in the organization you are, the more optimistic you tend to be. If one manager says "I can do that in 4 months", and another only promises it in 6 months, the 4 month guy gets the job. When the software is 4 months late, the overall system complexity makes it easy to assign blame elsewhere, so there's no way to judge mis-management when it's time for promotions.
To look good to their boss, most people tend to put a positive spin on their reports. With many levels of management and increasing optimism all the way up, the information reaching the VPs is very filtered, and always filtered positively.
It reminded me of a project I was working on where I wanted to create a web application to do the work and someone else on the project wanted to create it in Access because "that's the way we've always done it here and because it's faster." I estimated 3 weeks to get the functionality created in a website with some benefit of being able to re-use much of that work on future projects. The people pushing Access promised 1 week to get it done. Decision made, do it in Access, we don't have time to do something that's better but will take 200% more time. Well, it took 4 weeks to get it done the first time. Then, there were bugs in it and the process of touching all the desktops to roll out a new version took almost a week in itself.
Shit may roll downhill in an organization, but sunlight definitely seems to shine directly uphill.