Keyboard Shortcuts? We'll Take Control-V, Thanks

According to Microsoft's user tracking data, the most common action in Word is pasting, and the most common way of doing it is to use the Control-V shortcut (followed by the right mouse button). This raises two interesting issues: given the popularity of using the keyboard, why did Microsoft spend so much time on the ribbon? And if paste is so popular, why did Microsoft make something of a mess of improving it in Office 2010? [Microsoft Office 2010 Engineering]