A sound barrier for silicon?

Microprocessor manufacturers have undergone a major shift from switching the speed of a single processor to increasing the number of processors that can work in parallel. A simple approach to scaling is just to shrink all the linear physical dimensions of each field-effect transistors by the same factor without disturbing the supply voltage. The mobility in the channel could be enhanced by using Silicon and Germanium alloys straining the channel, or even using different wafer orientations. Marketing campaigns have de-emphasized clockspeed and stressed power management and less tangible features including compatibility and reliability.