I think framing the discussion this way forces us to think about the pieces of the computing landscape that are not pulling their weight. A decade-old workstation has the benefit of a few things a pocket computer does not:

• Pointing devices (mice, trackpads, styli, etc.). These are only as useful as the software which takes advantage of them. There are already numerous examples of the value of Natural User Interaction, and some would argue that we can simply design ourselves away from the need for pointing devices. But I believe there will continue to be a number of tasks which will benefit from the ability to quickly move between arbitrary points on the screen (without touching it) and to adjust the movement ratio between our hand and the cursor.
• Keyboards. These remain both the dominant and universal method for human input, and are a keystone to the basic value of the Internet. I will gladly entertain the debate over speech some other time if we can all agree that one of the main reasons the display sizes of both the iPad and iPad mini have proven to successful is that they allow a proper keyboard to be rendered on-screen.
• Large displays. These have to be the greatest advantage to the workstation over the pocket computer. Being able to see more of what you’re trying to, well…see, is of obvious value. I can report that sitting on my couch with a wireless keyboard and trackpad, looking at a 55-inch television has been a revelation in how I use a workstation.
• Software. The types of tasks that can utilize these interface components are unlikely to change so long as human beings continue to perform them. Photo editing, video production, spreadsheet manipulation, and word processing are all scenarios that a modern pocket computer can easily handle from a computational horsepower perspective.

What then is the limiting factor between pocket computers and workstations? It’s not computational horsepower, and it isn't network connectivity, and it isn't really storage either. If we could connect a pointing device, a keyboard, and a larger display to our pocket computer, would we not be able to get more done with them? I think so. What though would be so much better about hooking up a pocket computer to these interface components?

The motive underlying this desire is personalization. Whether because of its portability or its primary use cases (communicating with people, documenting your life) the pocket computer is an intrinsically personal device in a way that workstations never needed to be (in fact, if you’re Scott McNealy, never should have been). The value of a computing device as an extension, proxy, or representation of yourself is at the core of the pocket computer. By virtue of it being on your person, dawn till dusk, everywhere you are, servicing the majority of your computing needs, it is you. The pocket computer is your personal identity object. Your spirit device.

For longer than I can remember, I've ranted about my spirit device. Much of its ability and function is obvious; horsepower, capture, memory, awareness, etc. But the criterion I've held onto above all else is that it shouldn't require luggage. If I have to do anything in particular to have it available to me, it becomes modal and a chore. No matter how thin and light laptops get, they demand that I throw a bag over my shoulder to be of any use at all. My spirit device doesn't require such coddling.

One could argue that the smartphone fits this bill, and in many ways I agree. It’s ideal for snapping a picture, writing down an idea, or taking a call. However I believe that for the third place, be it the cafe, the train, or under my favorite tree, the small size of a smartphone is a limiting factor. As I write this in my favorite coffee shop, I have a 10-inch display that makes it effortless to read what I've written without holding it a foot from my face, and an attached keyboard that allows me to type quickly. However, when I pick it up in a few minutes to head home, it’s large enough that I will be overly cautious holding it in my hand while I walk. And it certainly won’t slip into the back pocket of my jeans.

My other point of frustration is having to rely on a different device when I get home, or to the office. Because in order to utilize the large displays, keyboards, and mice in those locations, I have to move to a workstation. I have to rely on sync services like SkyDrive and Dropbox which while effective, are in many ways just elegant bandages. Why should I have to rely on transporting the state of my computing environment over the Internet if it’s already moving around with me everywhere I go?

Everything that fits in my workstation fits in my pocket computer. I just want my fucking keyboard and my fucking display back.