I think one thing that is involved in this is conventions, and when you've learned one set of rules on how to communicate on one form of interface that it transfers to other applications on that interface. If there's certain ways to use graphical elements, gestures, console keywords/option flags, spoken keywords, while other applications have the freedom to do their own thing it should be seen as better not to diverge and reinvent the wheel (so each needs learning its own rules) too much without good reason.