This reminds me of an idea I had in mind a while ago.

It would've been similar to this (like some kind of "Startup Graveyard") but slightly more extensive: interviews with the founders and the lessons they learned from it, what "type" of failure they suffered from (misinterpreting the market, lack of skills, etc).

I ultimately gave up on the idea because none of the founders I contacted wanted to truly spill the beans on what went wrong (the best I tended to get was some vague PR mumbling).