The way to position PC's, laptops, tablets and smart-phones against each other is according to the content function you're trying to perform plus the specific requirements of the HMI (Human Machine Interface) needed.
You either create content, or you consume content.
For content creation, the HMI needs to be as effective as possible. A PC with dual 24" monitors plus a full size keyboard will allow the most efficient way of creating content, be it writing, CAD, programming, etc. Numerous studies have shown the improvement in efficiencies by increasing monitor sizes. For example, for Excel, a 100% improvement in creating sheets were shown going from a 17" to a 30" monitor.
As you reduce the HMI elements in size, possibly for mobility, efficiencies start to drop. A laptop is less efficient, to create content, than a full desktop and a tablet even more so. A smart-phone is right at the bottom of the pecking order.
To consume content, you can easily live with less efficient or fewer HMI elements, especially to enhance mobility. In a pure content-consumption environment, you don't need a mouse or keyboard. The screen size will influence efficiencies though, so bigger is still better, within reason. A tablet is more effective for reading than a smart-phone.
So, you use a desktop to create content, a mobile device to consume content.
Because most people will typically only have one device, laptops became dominant as a trade off between efficiency and mobility. A perfect example of "jack of all trades, master of none".
With the advent of tablets, offering improved mobility without compromise on the HMI required for content consumption, we'll see a return to the 2-device environment, a PC and a tablet.
Personally, I've been using a tablet for the past 11 months in addition to a full desktop. In those 11 months I've not switched my laptop on once. All content consumption is on the tablet, all content creation, past a short e-mail, on the desktop.
nail on head -you hit it
