Originally Posted by DreamWriter
How much more would it cost the manufacturer to include an SD card slot? It does seem to be a feature desired by a lot of people, so why not include that as an option?
Although many will give the simple answer that they just want to be able to charge you more for the models with more storage, the other reason for excluding it is complexity of the UI.
Where do you install an app? Where do you save it's data to?
What if you have two different versions of an app, one in main memory, one on an SD card?
What happens if you've got a shortcut on the desktop to an app on an SD card, and you remove the SD card?
Can you install widgets on an SD card?
What if an app has registered that it can handle a certain filetype, and then the SD card it is installed on is removed? Do you just fail to open that type, or be clever enough to display a warning explaining what has happened?
All of these issues are solvable, but they increase complexity, and make things more flexible, but less simple, for users.
Apple's design concepts have always rated simplicity higher than flexibility, and once they have excluded SD cards, it is easier for their competitors to do the same.