Steve Jobs was always about the next big thing.
By now, most people understand "Post PC" to mean the focus of innovation, growth, and profits in the technology sector has shifted away from the PC. In introducing the iPad, Jobs likened the PC to a truck while the iPad was more like a car. Most consumers don't really need a truck he implied, but he never meant to suggest PCs were going away. What if Jobs got the analogy slightly wrong and the iPad is more like a motorcycle?
Motorcycles are wonderfully convenient for quick trips around town. They're easy to ride, quick to park, and economical to run. But they're not well suited for family vacations, long trips, or even inclement whether. A lot of people who own a motorcycle still need a car. Some use their motorcycles mostly for fun.
In some parts of the world, a motorcycle might be all most people can afford. In more developed countries however, most working adults want access to a car. Imagine if there was no such thing as a motorcycle until one company got the idea. At first, demand for this novel and cheaper mode of transportation would skyrocket. Some might even predict the end of the auto industry. Within a few years however, motorcycle sales would level off. The auto industry would be smaller but continue. Someday, the auto industry might even become a hotbed of innovation again.
The iPad is revolutionary and disruptive, the PC is no longer the only mainstream computer in town. Where I differ with some predictions is whether tablets are the future of personal computing. I think people are conflating different things.
Smaller, lighter, instant on, always connected, all day battery life, these things are no brainers. But comparing an iPad to a MacBook Air or similar, I think both have their place. These products are designed around different user experiences. Much of the battle over the future of personal computing is still in the cloud.