I was a part of a start-up that was technically successful (investors somewhat happy), but it really didn't meet our early expectations.
I had my own set of post-mortem analyses; I'm sure everyone else in the company had a different set.
So I appreciated a founder's review of a start-up that really did die: Monitor110: A Post Mortem, even though they probably have an element of self-protection in 'em. That's inevitable.
I'd heard one of 'em before: "Too much money." Counter-intuitive, but a common item in the post-mortems I've read and heard.