Why? Because they had a world wide launch of their best selling product set for a certain date. That's why. I use to be a senior product manager at one of the top 10 software developers and you make trade-off's to hit launch dates. I'm sure they knew they were going out crippled... but also knew since it's software they can fix it quickly and cheaply. Stopping the iPhone launch by even a day would have cost Apple and their partners millions of dollars a day. That is why they did it.
And wear the pain being described here (by predominantly Apple-obsessed consumers)? Failing from launch is supposed to be a Microsoft skill - not Apple. I readily admit that I have no experience in the industry, and I certainly respect yours, however is it not possible to prepare in advance, and (like other firms frequently do) push back a launch date? Apple appears to be so desperate to emulate the hype built up around it that it can't bear to appear normal. Everything has to be 'beautiful, magical and revolutionary'. Choosing design over function so obviously (antenna), failing to provide a reasonable product at launch (upgraded the software on a 3G lately? Remember the launch of MobileMe? Did you buy a 3G when it was first released and enjoy watching every - EVERY - app crash within 2 minutes? Enjoy the dead pixels? Whoops! Don't put you phone near your face! FFS) and patronising actual and prospective customers (again; hold another phone like this, with your middle finger on top of your head and your third toe doing the hokey pokey & you might drop a call) are the reasons I am seriously not getting another iPhone. I'm posting this to give people who come to this forum another side of the story.
By the way, for what it's worth, I went and looked at an iPhone 4 today and could not think of a good reason to shell out more cash for it over a cheaper phone - I've been addicted to iPhones but literally this month I've had it.