As early as 2003, a handful of Apple engineers had figured out how to put multitouch technology in a tablet. “The story was that Steve wanted a device that he could use to read e-mail while on the toilet — that was the extent of the product spec,” says Joshua Strickon, one of the earliest engineers on that project. “But you couldn't build a device with enough battery life to take out of the house, and you couldn't get a chip with enough graphics capability to make it useful. We spent a lot of time trying to figure out just what to do.”
via New York Times
This is the starting point of the first Apple iPad. At present I don't think that "to read e-mail while on the toilet" is the main purpose of a tablet. Nevertheless we all admire the visionary genius of Steve Jobs, don't we?
But between the vision and the final product there is the work of many people, a lot of sweat and many other strokes of genius. Don't forget this next time someone will say that a complex product is successful only because of a single person.