John Gruber nailed it on press events
There's been a lot of controversy in the form of criticism from The Verge team and also comments around the site regarding pricing and shipping of new products. John Gruber in his latest podcast really nailed it though. It's absolute hubris for companies like Motorola and Nokia to think they're going to stop any significant number of people from buying the iPhone by pre-announcing a product. The entire point of a press event is to drive people to buy your product now. Imagine if the Nexus 7 did not start taking preorders for a month or two after the announcement? Would it have gained nearly as much traction as it did? Unlikely.