over 65 words per minute, including proper formatting, there will always be a demand for desktops to do the heavy crunch work that is done every day in businesses and at home. Touch screen systems aren't that good for the preparation of most documents and many other business related tasks. Maybe a computer that interfaces direct with the mind will replace the desktop too.
Sure Apple are selling a lot of mobile devices, but they're still selling a lot of MacBooks and iMacs. Although the iMac has been seen as a niche player for many years, it's still going very strong.
Keep Up with TechRepublic