But as we move to smaller processes that require less electricity to function, perhaps heat dissipation will become a none issue.
The reduction of power consumption (and hence heat production, and the need to dissipate the heat) along with feature size is called Dennard scaling. As feature size has fallen it has not been possible to keep lowering the voltage and current proportionally.
But give it a few years, maybe 5, and something in a similar form factor will be much more affordable and will still be able to perform the role of a traditional desktop.
My phone has 3GB of RAM, a quad-core 2GHz CPU, and 96GB of storage, which would have been a pretty sweet desktop once upon a time.
Arithmetic is being able to count up to twenty without taking off your shoes. -- Mickey Mouse