I don't think people are getting dumber, I think the basic intelligence requirement for society is getting higher. My parents didn't have to take calculus in high school, for instance. Also, you need a bachelor's degree to get any job better than McDonalds server these days. So, a lot of people who in the past would have been considered average or even above average are now considered unemployable idiots because they're not as good at school as the rest of us.