The same goes for the keyboard. The layout will be tweaked for years to come to maximize the tolerance people show for the keyboard, and there is an ongoing redesign of the layout of speed keys, but the interface is defined and frozen. Other input devices are unlikely to make much headway. Speech recognition's only use is to let you keep working when you take that carpal tunnel-mandated break. Prolonged talking into the computer is a pitiful way to wreck your vocal cords.
Foot pedals are similarly unattractive.
As for the output devices, the speakers are limited in the interactivity they give. We use them mostly for music, partly because canned sounds as computer messages can get very tiresome after a while, and partly for privacy. The screen itself may get more versatile as it becomes lighter, or as LCD technology allows us to look more closely into it, but once again, these changes will not be earthshaking. MC is what is requiring optimization in the graphical user interface and limiting innovation. MC does not reward clever ideas.