Not all post-mortems are for failures/dead products which might add even more confusion. For instance Gamasutra runs a game development post-mortem section where developers of popular (and unpopular) games can hop on and describe difficult situations they've encountered, how they did what they did, why they did that thing, etc.

It's really fun to read.

http://www.gamasutra.com/features/postmortem/

edit: Wow, there hasn't been one since 2014. I wonder why this died out. There's 10 pages of them since 2007..