Ah.....
Oddly I finally understand the lack of an SD Card on an iPad.
Its not about forcing upgrades, well ok, perhaps it is bur it looks like its more about driving a shift to "the cloud".
Ok, so connections are slowly and limited, and from what I understand icloud is an issue, but thats the game plan, so in theory your iPad should never be full as you have terrabytes of online storage and you can access anything and weather its in the cloud or on the device the access is seamless/ It should be cheaper than buying a new SD card, and oh, guess what no copying from old card to new card, oh and even better easy sharing between your devices....
Perhaps SD Cards are a throw back to the times when we needed floppy disks to transfer data between machines, and to increase a machines capacity.
Perhaps its more a case of Apples reach exceeding its grasp.
*shrugs*