I disagree completely. Why don't you write all your books on an iPad? It's not the tool for the job. In my opinion 20 years from now, assuming we don't have cortical implants or similar, people are going to go to work and sit down in front of a monitor with a keyboard and a mouse. It won't be so different to how people worked 20 years ago.
MSFT completely agrees with you. The see the Zeitgeist going towards more and more devices so they are scrambling to make handsets and tablets that no one wants to buy. They totally ignored the core desktop user with Windows 8. But this has to do with being a publicly traded company I think. For some reason a slow and steady market like desktops isn't good enough. They can't go to the investors and say "We aren't the sexy new thing, but we'll continue to make boatloads of money for the foreseeable future." (Honestly I'm not sure why they can't do that, but companies have to plan on growing for some reason.)
At some point in time desktop was a must-have to get any meaningful work done. Especially a windows desktop. whatever the work may be. today thats not the case. In fact, lot of work cannot be done with windows desktop anymore. We need windows only to access windows specific legacy software, that enterprises are still using, such as outlook, excel, powerpoint etc. It is the IT groups in large companies that is holding the fort for microsoft. But, how long they can defend microsoft? Probably not much longer. Still intel is a major partner for microsoft. With ARM 64 bit coming in 2014, intel faces steep competition. ARM and linux go way better than ARM and windows. IT guys will eventually probably disappear foreever.
So you think the reason you don't walk into an office and see everyone using an on-screen keyboard on their iPad is because of legacy Windows software? We have Microsoft to thank as the last defender of the keyboard?