I'm not even going to read the article and just tell you all that an iPad is like 1/3 - 1/4 the price of a Mac, so in that alone we should conclude that it'll sell more.
Not only that, there isn't really a competitor to the iPad, whereas I can go out and buy 2-3 laptops for the price of a Mac.
Finally, for most situations, I can imagine the following happening:
Customer: Yes, I'm looking for a computer. Apple Store Guy: Okay great! What will you need it for? Customer: Um, checking my Facebook and Twitter, doing some email, and playing some games? Apple Store Guy: Okay, well you can get our entry-level touch-screen toy of the future, known as the iPad, for $499. Or, you can get a Mac for anywhere between $1500 and $3000. Customer: OMFG drool iPad please!
The customer just saved hundreds, if not thousands of dollars, and now has a fun way to check email.
Case closed.