FINALLY...I got an update that truly makes sense...
Great post!
I ordered my iPhone around 6 am on September 9. I started out with a 7 plus 256GB jet black and got an estimated ship date of more than 4 weeks, so I switched to matte black and got an order window from Oct. 4-10. I didn't try this, but I suspect that I could have gotten my phone much sooner if had ordered one of the less popular colors. (BTW, I didn't change my order just because of the delivery date.)
It'd be very interesting to peek behind the curtain and see how the iPhone order fulfillment system really works. In theory, it would be nice if there were one supply pool that all orders draw from, but I doubt that's the case. And there are factors that are hard to predict very accurately, such as which color/size/storage combinations will be popular—they can get close, but there's still room for error.
All this works in Apple's favor because it adds to the impression that the iPhone 7 is a huge hit. Front pages of non-tech news sites are saying that the 7 Plus is sold out worldwide. Every year, people complain about Apple's inability to meet demand, but it's unlikely that they buy an Android phone because of it.