Future = only geekos, and programmers like us are gona own a desktop computer, that will become a "niche" (little part of the market) maybe 15 ... then few years after 10% of the market
I don't see it that way. The flat screen TV market has driven down the cost of computer monitors. The mobile computer market has optimized PC hardware. Without smart phones and tablets, we would still have clunky hardware.
The "desktop" label only implied the device _required_ a desktop (ie: computer desk) to hold it (plus a decent power supply). Which was not a great situation.
Give me a cube PC (or notebook), and I will still want a big monitor/keyboard/mouse, which require a desk. The only device there that is expensive, is the monitor, and as I said, the cost of that is low because of the flat screen entertainment market.
So, who cares if they don't sell big boxes anymore. I prefer to think of it as "desktop usage", and "mobile usage".
Its all the same technology, just with different user interfaces suitable for different situations.
ie: I have a notebook which I plug into my monitor/kb/mouse to work with. So, is that a desktop PC or not?
I'd say its not possible to measure how many people actually use "mobile" devices as desktop PC's.