Hmm, title of the thread made think that this was a documentary about Steam.
The actual subject sounds just as fascinating, though. That is a lot of dead projects, and it sounds like what I've suspected was Valve's problem for many years was true: that their ethos of working whatever you wanted only gets games to a prototype stage, which is the part of game development that is fun. It doesn't get you to a viable product, which is all the bits of gamr development that isn't fun. Will certainly take a look at it next week.
Edit: sounds like it only focuses on Valve's game development, though, which is only a third of the studio's story. I hope that there will be other documentaries on their hardware divisions, and on Steam.