Tablets are simply not as useful for the huge majority of people as a laptop is.
And that is due to the lack of good input. You can work around, but it's no substitute for a touchpad and a keyboard, period.
The longer you use a tablet, the more you realize that it's a solution in search of a problem.
At first I thought that I'd lounge around the house with a tablet and not need a laptop, but even then, if you're instant messaging, or browsing, whatever.
You're always going to need to do input, and the moment you input anything more than twice, over the months, you'll realize that a laptop is simply the superior choice. It's not due to familiarity and a resistance to change. Laptops are just completely superior for the vast, vast majority of people.
Prediction: the watch will go the way of the iPad as well. Huge initial interest, relegated to a niche role after 4 years.
We need true innovations in battery life, screen technology/form factors, and sensors to make the next leap, and Apple ain't going to provide it. They'll probably buy the company that makes it and call it their own. Apple's a spit and polish type of company, and there's nothing wrong with that. Taking promising tech and mass producing it is not easy, but let's not kid ourselves--this is what they do.