The answer is interesting; it’s because they can’t. Apple won’t let them. If a label has uploaded an album to the iTunes Store and wants to add a digital booklet later, the only way they can do this is to delete the original, and create a new album listing with a new SKU. And if they do this, then purchasers will no longer be able to re-download music listed under the old SKU.
Chris Greening (via Jonathan Wight):
Sudoku Grab is a collection of some fairly basic image processing techniques that most engineering students at University could probably figure out how to put together. All of the algorithms used are either commonly available and can be found on the Internet or can be written pretty easily. Obviously tweaking them and getting them all running together seamlessly is the real trick…
The other issue that this kind of quality control can’t cover, is services and frameworks where Apple itself has no internal clients. The biggest example being Game Center.
There are other examples of this problem, the most obvious of which is probably the application sandbox.
Update (2012-10-26): See also the Hacker News thread and more from Wagner on Game Center, Letterpress, and Lost Cities.
In the end, the “up to 150 Mbps” or “2x” improvement is a sort of silly marketing point that should have been confined as a note in the tech specs and not trumpeted as “advanced,” “new” or, in fact, in any way special during the launch event. Adding two-stream or even three-stream support to future iOS devices would have a greater impact on improving throughput than this channel bonding tweak affords.
