When you hear tidbits like the multi-touch pingpong table which lead to iPhone, it feels like the iPhone was a one-in-a-generation new product category.
Actually, it points out how much parallel R&D goes on. Everyone and their brother has been working on touch systems for decades, table and hand sized, multi-touch and even multi-user touch. The general public doesn't know much about this history, though.
I think the popular notion of it really started with Tron's 1982 touch desk:
And of course, 1987's Star Trek - TNG:
By 2001 or so, there were multi-user/touch desks available if you had the money. By 2006, the year before the iPhone was revealed, you could even buy a simplistic multi-touch bar top:
Also by 2006, full screen and multi-touch concept phones, some with features such as pinch zoom, were all the rage:
It was even predicted that capacitive touch screens would begin to take over the mobile market in 2007.
Out of all this, Apple had two huge advantages: 1) no legacy phones that required non-touch support etc, and 2) a CEO who wanted to break into the market in a big way, and who was willing to cannibalize his current iPod market if necessary.
OTOH, Microsoft, whose R&D sections not only had the Surface multi-touch table well along, but also had the incredible Courier dual display tablet in the works, just plain blew it by wanting to protect their legacy Windows products. They marketed the Surface to hotels, and shut down the Courier project.