Well yes,..
If the issue is purely the tech just isn't ready then throwing cash at it won't help.....
but Apple has a big horde of Cash so if the issue with the parts is the economic risk of retooling to build them and ramp up production. Then that is something pre-buying maybe able to solve.
I think some people are forgetting other elements are involved with the creation of a phone model. Sure, Design has a lot to do with it, as does the supply of parts.
But Apple isn't just some backstreet hack knocking up burgers, reliant on the supply of produce that will match their recipe.
The product releases are scheduled. In the consumer electronics business, the technology needs to progress rapidly, rolling old products into obsoleteness.
Deals related to parts would be in place more than months ahead. Chances are, the iPhone 5 was already beginning testing before the iPhone 4 was released.
Which means, even at prototype level or pre-production sample, the components would have been available long beforehand. You think they knock off 5 million iPhones between announcement date, and release date with complete faith in shipping schedules?
Deals relating to the supply of these parts are made long in advance. Manufacture for the iPhone 5 would have already been getting ramped up, and the need to have the new product available at, or around the existing schedule would be vital. And they wouldn't be taking chances. It's crucial in the IT industry.