Heck even back when I was in school, I barely did any homework or studied at all, I lived to go home and play video games every day. I was able to skim through because traditional school had such low expectations, but without proper studying I did not learn any of the material that I tested so well on. As a result I had to retake a lot of courses when I got to college.
A much more authoritarian environment in school would have been good for me. Two periods free of distraction dedicated to studying (perhaps spread throughout the day) would have resulted in my learning a lot more.
One saving grace might be if the majority of students who go to these schools have parents who expect excellence. In that case peer pressure will force many students to take the same lessons that other students are. I suspect that so long as the school sizes stay small that it will be possible for such forces to dominate.
Running a 2000+ student public school within the context of a community that has little expectations of academic achievement? Good luck graduating students who are even literate. (One can observe low literacy rates highly economically depressed areas already!)
More fundamentally, sites/services like Reddit, Facebook, Snapchat, Instagram, etc, all directly tweak the pleasure center of our brain. By design users will not get bored of them. Yeah yeah half the users on HN will get bored of Snapchat/Facebook/Instagram, congrats, we aren't neurotypical, I don't get a spark of pleasure looking at pictures of people on some social network, but I sure as heck know others who can literally spend hours just browsing photo streams.
TIL on Reddit however? Or heck just HN itself? Yup, very addictive. Learning new factoids feels good.