Even if we do head for a teacher shortage I don't think it would be for some of the reasons you are mentioning. The biggest problem threatening the number of applicants has nothing to do with what the job entails, but how they become qualified. The number of people pursuing education related degrees really started to fall in the early 2000s. What else happened around that time...the price of college. The price of college has exploded so much most people are pursuing degrees that make them $$$. No one wants to spend $50,000+ to start out in the $35,000 range and top out at $55,000. Now if such a shortage happens will it really get so bad the teachers are unqualified to the point it hurts the learning experience of kids? Possible, but hard to really say.