For example, think back to Google Glass. There was a time when it was an amazing revolution about to happen. There are pictures of generally smart, experienced people wearing Google Glass and trying hard to look like the future. [1] How much got spent there? On the glasses alone, figure it was something like 100,000 units at $1500 each for a total of $150m. Google presumably spent a fair bit more on R&D and marketing, and plenty of other companies spent time and money on the platform.
Were all those people dumb? I never understood the appeal of Google Glass, so you'd think I'd be inclined to say so. But my take is that the people who gave that a go were just working with different heuristics than I am. Lord knows I've bought plenty of disappointing gadgets over the years. As long as we're write more often than we're wrong, the heuristics aren't bad, just not perfect.
So here I figure that most of the people who put in money weren't idiots; they just had different ways of judging. E.g., a lot of deals happen partly because of trust. But we all know that con men are people who are extremely good at manipulating trust-related heuristics.
[1] http://www.forbes.com/sites/tomiogeron/2013/04/10/google-lau...