"However, most of the large-size tablet projects face difficulties because of lack of support from related platform developers and ecosystems. Apple has also been said to shelved its large-size tablet project."
If i were Apple, i would be listening with all ears..
It's clear its not going to be a product. When you hear .."It's put back on the shelf" then you know it could be bad, its on hold for a long length of time. maybe indefinably. The small size tablets only went ahead because its was an acceptable screen size.... Start making it too big, and you have problems like this.
Fact is, if no one wants to support it, then its not a product from my point of view. I may be wrong in the future, but this looks like it at the moment.