Sorry, that's not going to happen. People are people, not machines, and if you tell them all the discovery and excitement of UI design has already been had by past designers, and that all future work should be purely derivitive, you won't have that many people staying in UI design. You're going to have to learn to live with the fact that creative people don't want to paint by numbers. Same applies to every complaint about new generations of people reinventing any wheel that applies to their field.