You mean all the recent backorder and supply problems? It's an age old marketing ploy in the tech industry. When something is limited in supply and hard to get, people want it more and line up in droves with more deposits and preorders.
It may seem counter intuitive and you'd think they would lose money by limiting supply when you have customers lined up with their money, but you create an aura of elusiveness that drives people to want it more, and you trade short term launch day sales for long term continued sales by trickling them out. It's a balance between keeping supply just short enough that hype and demand stays alive until the end of the product cycle, but not limiting it too much so that you don't sell enough that people give up and just get the next newest thing coming out in a month.
have plenty of supply:
week 1 - 7 million sales
week 2 - 4 million sales
week 3 - 1 million sales
Keep supply limited and on back stock to create hype, exclusiveness, omg gotta put a deposit on it and get one NOW!!! BEFORE ITS TOO LATE! Hype and fear of being left out is basically free advertising; the hope for the next shipment.
week 1 - 5 million sales
week 2 - 5 million sales
week 3 - 5 million sales
See how that works? This kind of tactic has been going on for years (including such things like Wii, Geforce cards, blah blah blah blah. etc). Seriously, this happens time and time and time again; do you seriously believe companies are as surprised as they act about not having enough.. for the 1203784th time? It's a well calculated marketing tactic. In the case of the Wii, remember how it was on out of stock for like a year with people paying double/triple MSRP, meanwhile it was found that they had thousands of them sitting in a warehouse on pallets, not being shipped. Anybody remember those pictures?
Obviously we know in some specific cases like the HTC AMOLED problems and what have you that might pose a real physical production capacity limitation, but not EVERY. SINGLE. DEVICE. ALL. SUMMER. Most of the time it's not necessarily a production problem, just creative marking that plays with peoples emotions and feeds on a greater desire to have something if you think you won't be able to get it to keep demand alive in the long run.
Also it continues sells into the next newest product that might otherwise have been lost. Think about how many people have a back order on a Incredible or Evo or something that will will still be getting their phone in a week despite new phones like the Droid X being out; all those people "locked" themselves psychologically to the product on back order that they put their name down for on that next shipment coming in. Too busy spending weeks calling stores and tracking down info on that elusive next shipment, they don't even notice what they want is now obsolete and they are still after it. People are so "gotta have it" that their attention span remains focus on getting what they couldn't have a month ago that they don't even notice new stuff being out sometimes. In a way it's selling hope, similar to games like WoW that keep you playing on the premise of hope that next time it will be your turn (on a random drop in the case of WoW).
This last concept is very similar to hyping consoles: announce amazing impossible specs 2 years before the first production unit, people go insane over it and talk about how awesome it is, etc. In the mean time in the 2 years it takes to come to fruition, specs end up being 1/10th of what was initially announced, but it doesn't matter because that hype and excitement from the original announcement is still there and still strong in most peoples minds (PS3 anyone?)
Mmmm sociology. Obviously most of us on AT are unaffected by this, most of us would cancel a back order in a heartbeat if something better was coming out, or give up and find an equivalent device, etc. But think about the masses play into this psychological warfare...