While in theory you are correct, there are a few points to ponder upon:

Laptops are not like stocks or other exchange commodities. As in, their prices won't fluctuate like crazy (unless of course you manage to get pre-order commitments to like 10,000 laptops.) At the scale we are talking about, we have a pretty good idea of what price discounts we'll get. And more importantly - who will be able to deliver them well.

Its important to keep scale in mind.