I think millenials (because I'm old and my kids are millenials) but also because I think the teaching methods that have been used in the US, the learning standards, are so outdated, boring, and I just don't think kids are engaged anymore. That was my experience about 11 years ago as a teacher and I had to strive to research how to make learning more interesting. One problem is textbooks. Grades 1-12 textbooks are not only boring but outdated and inaccurate. The other is rote memory. From a special education teaching perspective, make "school" more like how we learn in college (collaboration, technology, real-life uses) would turn a nation of robots into geniuses.