Actually I may as well explain my reasoning for the Wireless, Blu ray, HDD increase.
Microsoft makes money when people make use of their profitable online services. If people go online on gold they earn $50 per year revenue in addition to whatever they earn from the other services they use on Live as well. Wireless is simply to encourage people to go online and use the media centre features and to make sure that the people who need wireless don't go looking elsewhere for their console purchase.
The Hard Disk drive is 20gb - but it only leaves about 10gb of free space after formatting etc. So that means that it acts as a limiter for people to purchase online content because there simply is not enough space on the hard drive. An increase to 60gb will give the console between 4-5 times the free space it has currently so they can expand their media offerings and therefore the profitability from their movie/game downloads. Furthermore it does help to make the console look more impressive than the PS3, go figure I know. But I worked in retail and literally 20% of the potential buyers I estimate will be impressed by the fact that its a bigger number than 40.
The reasoning for the blu ray in the Elite is simply because it is the Media centre SKU. It has a larger HDD specifically for use as a media centre. This SKU suffers from an identity crisis. Its existance is hard to justify at present and even harder to justify if the HDD on the Premium SKU is increased. The target market for a media centre overlaps heavily with those people who would also appreciate blu ray so for those people it makes sense to give them what they want in one package. A complete media centre.
Now the expenses. Wireless would cost very little to add, and the potential profit from those who go online because of it would probably cancel the added cost out anyway. At most I would say it would cost $5 to add wireless. My best guess is about $3 each in quantities above 1 million consoles. It requires a motherboard revision so this is the only chance for another year for them to add wireless to their consoles. .
For the HDD, I checked a price search engine and discovered that the price for a 20gb HDD is the same price as an 80gb HDD. Its quite possible that a HDD size increase would cost no more than $5 and even that would drift back down to 0 as the costs decreased over time. It makes sense from a profit/cost perspective for them from their live services to make this change.
For the Blu ray - The cheapest drive is $130 on Newegg for a retail drive. If the price of the Elite is maintained at $450, the console would be easily profitable with the drive installed and maintaining the same price. I would expect it would cost them less than $100 in quantities over 100,000 drives to buy them on the wholesale market. So long as the PS3 maintained its price in the US this SKU could easily return to the profitability it had previously as the price of the drive lowers over time.
Tease.
