Lack of wisdom. Perhaps inexperience.
That actually makes a lot of sense. You have to get burnt once or twice, I think, before you are really capable of being realistic about investments. I remember getting all exciting by the tech bubble, and losing money when it burst. Fortunately not more than I could afford to lose, but until you've got caught up in the hype at least once; until you've let yourself believe all the very plausible-sounding reasons why "this time it's different", it's very difficult to really appreciate how utterly wrong the majority can be. I'd frame it not so much in terms of greed but rather in terms of wishfull thinking. It's an important lesson to learn, and not an easy one, nor a pleasant one.
Lets consider a much simpler investment: simply holding a bunch of bitcoins in your wallet. I periodically think long and hard about whether it's sensible to hold coins long term. Whether it's realisitic to be bullish about the value of BTC or just wishful thinking on my part. I'd do that even if BTC was appreciating and everyone was confident it was a good investment. In fact, I'd do it especially if BTC was appreciating and everyone was confident it was a good investment.
This is why people with poor business models like BFL can thrive in this environment.
BFL, on the other hand, is a completely different kettle of fish. Seems like a typical start-up to me. I think a lot of people here are so used to mainstream present day tech companies and they either weren't around or don't remember the days when pretty much all tech was built by companies stuggling to complete and ship cutting edge products on time. The Sinclair ZX80, the BBC Microcomputer - the even earlier single board computers. All suffered from slipping dates, production problems, etc.
Yes, dealing with a start-up like BFL involves making some calculated risks, particularly if you choose to preorder a product knowing that it's not yet in production and therefore the final specs aren't yet known. It's the nature of start-ups that some businesses fail; and it's even more the nature of designing technology products that things don't always go according to plan, and often (some might say almost always) takes longer than expected. I happen to think these risks are acceptable, and I took them (with money I can afford to lose) and preordered an ASIC Single. For me, though, it's just a bit of fun; whether investing in mining equipment (or any kind) is sensible thing to do as a serious investment, I'm far from sure. The days of easy money from mining are gone, I think