It's really annoying that nobody seems to have them ready to ship, but they will take orders 2+ months in advance despite the risk of missing the reward halving.
Its because of those risks and the risk of other ASICs coming out earlier or taking preorders earlier. Its understandable from the supplier POV; if you wait until november or maybe even december and you have shelves full of products ready to ship before taking orders, you may find the market saturated already by one of the other vendors, difficulty above 100M and prices in the toilet. Preorders is selling this risk to customers. BFL started it, others have no choice but follow. There are now 4 asic producers saying they will have product this year. Its a big gamble, not everyone will win. I think most will lose.