Saw Intel's ad for convertible laptops. (Guy breaking his old laptop with a cup of coffee so his employer would have to buy him a new computer.)
The tag line at the end is "A Laptop when you need it, a Tablet when you WANT it."
Even right there in the ad saying that a tablet is what people really WANT ("want" was very emphasized by Mr. Lipton doing the voiceover).
Yes, many people still need a laptop for work...but that's not what they want. Given the choice, people are going to buy what they WANT.
(And I've seen more and more iPads out for work too. At the grocery store yesterday and a manager was using one to track something. Before, he might have had some specialized device or even a paper printed report to check off; I don't remember ever seeing someone with a laptop walking around doing inventory. Now it's an iPad. People who say tablets aren't for work are only thinking about their one specific job type.)