That isn't news. However, the egalitarian fantasy which nobody truly believes hangs over much of America's educational industry.
Efficient primary education for the masses probably does work best for the most according to the Prussian model which American schools adopted during the 1800s as primary ed became government-run. One-size-fits-all authoritarian ed is in fact efficient, if terrible for boys, to learn the basics of readin, ritin, and rithmetic that any citizen needs to function in the world. The fundamentals are not much fun unless there is competition added to the mix.
When the primary school basics are not achieved, I tend not to blame the school because there are too many external variables at play.
When it comes to post-primary ed, the external variables increase. Native curiosity plays a larger role, as does family support and structure, IQ, etc. etc. However, the Prussian model begins to work less well for boys as they grow up. But I am wandering from the topic: According to Albert Jay Nock, America's theory of education is off.