The fast, full-color, accurate, low-power finger-touch display has only been around for about five.
Imagine what touch-based UI will be like when people ascend a learning curve for it akin to learning touch-typing in the 7th grade.
What will daily life be like when we all know gestures for "find this on a map", "mark this on my to-do list", "unlock the door", "set the timer for nine minutes", and "leave a note here"?
What will musical instruments be like? What will museums be like? Store aisles? Textbooks? Menus?