If the years following January 2007 have been any indication, touch is rapidly fulfilling its destiny to become the predominant human-computer interface, and it will have a reign spanning multiple decades.
Desktop and laptop computers are essential tools for people in a wide variety of fields. Many of the tasks they’ve come to tackle were hard to even imagine thirty years ago, but calling them “personal computers” hasn’t masked the fact that they haven’t been much more personal than your letter opener. Traditional PCs require that you come to them on their terms, overcoming numerous physical and intellectual abstractions. The iPad was the first computer built to meet you on your terms. It brings the last 35 years of digital technology into the physical world in a way so natural, not only do grandmas and toddlers get it, but so do kittens and lizards.
If we aren’t counting iPads and other tablets as PCs, then PCs are well on the road to becoming a radically less relevant category, falling fast and hard. In twenty years, the computer an average human uses will look a lot more like an iPad than it does like a PC. That is, if tablets aren’t PCs, in twenty years people will be saying “what’s a PC?”