Gruber, speculating on the original iPad:
But there’s one question at the top of the list, the answer to which is the key to answering every other question. That question is this: If you already have an iPhone and a MacBook; why would you want this?
Turns out, there is a market for a form factor between the iPhone and the 9.7” iPad, the iPad Mini. So the question now is this: If you already have an iPhone and an iPad; why would you want this?
Gruber answered the question later on in the article:
And so in answer to my central question, regarding why buy The Tablet if you already have an iPhone and a MacBook, my best guess is that ultimately, The Tablet is something you’ll buy instead of a MacBook.
iPad:MacBook :: iPad Mini:iPad ?
The iPad Mini will be much more portable than the iPad, and will be much more suitable for content consumption, especially anything to do with reading and web browsing. So, as the larger iPad takes on a more of a content creation role, the role of a Mac, the iPad Mini will take on the role of what the iPad does today.
Maybe, the iPad Mini will become the dominant tablet form factor, like the iPod Mini/Nano, and the larger iPad will be discontinued, it will be a interesting to see what happens