Back in the 1990s I came across a site describing a plan for returning to the moon via privately funded enterprise. They presented a Reference Mission, a timeline (raise some money now, design the hardware, build the hardware, hire a launch vehicle, get to the moon, sell the movie rights) which had them starting to build hardware in a few years and touching down on the moon only a few years later. I even met one of the enthusiasts.
What I found interesting at the time was a presentation of the "Frequently Raised Objections" and their counter arguments. Their viewpoint was "we've got this completely solved--we're going!" The primary issue seemed to be raising the money, and this was covered by a business plan at least to some degree of detail. Of particular relevance was "It's all on paper, nothing is real". Wow, take that Mr Frequently Raised Objection.
Most of their points looked fairly reasonable in isolation, but of course the idea has failed completely. No launch, no hardware, and very little money. High confidence in the business plan despite little supporting evidence seems to have been the major problem.
I can't help thinking of these guys every now and then, with their nifty ideas like ascending from the moon with the astronaut sitting on a rocket motor in his spacesuit with no spacecraft needed. I guess the detail made the Planning Fallacy seem less likely at the time.
The parallels with some other ventures are striking.