Yes, I did say iPad Nano. No, that is not a type-o.
Remember back, just 20 years ago? Who would've thought that laptops would have revolutionized mobile computing the way they did? Obviously someone. And who could have foreseen how, within a short time, laptops would come in sizes ranging from less than 11 inches to almost 2 feet!? But they have.
Now it is the age of the tablet. In this post-PC phase of computing evolution we are seeing the market dominated by both higher quality and more varied options of smartphones, “phablets” and tablets.
Personally, I say it's inevitable that Apple continually expands its product line, certainly if they wish to remain the dominating presence of the technology industry. Apple may not be “forced” to do anything, but they have, and will continue to see the intrinsic value inherent in offering an ever increasing variety of product options in terms of iDevice range, capacity and physical size.