Remember, if the customer has $1000 left over after buying his first 10 units and wants an 11th it's best for Apple that the purchase be delayed several weeks so that the customer buys a new unit from them for $500 rather than have him fork over $700 for a unit Apple already sold to someone else.
Every retailer knows that it's his money in the customer's pocket, and the trick is to get that money into his own pocket ~ and not just handed over to strangers!
That is an EXCELLENT insight! Thanks!