If Apple sells 72 million units it will be an unprecedented number, well beyond the expectations of any reasonable person. The only way your scenario plays out (based on my comment) is if the stock price is above $140 on the day that Q1 2015 is announced.
Why this wasn't obvious from the start is a mystery to me.
The iPad, as complex and wonderful as it is, is not really ready for prime time. Never has been imo.
Great for content... not quite up to the task (yet) of workhorse.
I give it another 4 or 5 years. Tops.