People are not dumber, the stuff they care about is whats changed. They emphasize pleasure, social acceptance, and stuff like that which are mostly not conducive to growing smarter as a society as well as the amount of people there simply are. We've been able to find negative Kelvin temperatures I'm recently finding out. That's how smart some of the people that live today are, the only reason you hear so much about dumb people is that they tend to believe they are smart and make a big splash on the media where as many smart people simply do their work which doesn't give allow to a lot of media coverage. Also once again because of the change of focus as a society Scientific and Mathematical discoveries simply aren't as interesting to people to highlight on the media as they were centuries ago when as a society we we're focused on learning.