You're mostly right here, but making things specialized to the extent that Apple is doing here often makes things more expensive. If you go the specialized route instead of using commodity hardware there's going to be a big upfront price. Its possible that reduced packaging could make up for that in some cases, but I'm skeptical. There are also some changes that Apple makes simply to prevent user serviceability, like special Apple only screws, that don't help with weight and only serve to increase the price.