Apple tends to pre-pay manufacturers (of e.g. LCD screens, flash memory, etc) large sums in exchange for lower per-unit prices and first access to the supply chain. This results in Apple's part orders taking priority over everyone else's for a specified length of time.

There was a time, not too long ago, where every MP3 player manufacturer in the world had a hard time getting flash memory because Samsung, the world's largest manufacturer, was selling most of its supply to Apple. Thanks to the tendency of such large companies to operate each division as a separate business unit, this meant that even Samsung's portable phone and MP3 player division had a hard time getting flash memory.

In the end, prices went up for everyone except Apple, since the supply was severely depleted.

My understanding is that Apple has done the same thing for 10" 1024x768 LCD screens, resulting in a diminished worldwide supply (and, as a result, an increased price for anyone looking to purchase them).

And they have reportedly done the same thing for larger lithium polymer batteries.

I wouldn't be surprised if they were already lining up whatever the next major battery tech is going to be as well.