You must realize, education was a bit more accelerated back then to get boys out of school faster and into jobs or college sooner so they could be in the workforce or army. Many boys ended their education at highschool, some before they turned 18. Also, when learning things at a younger age, you absorb the knowledge faster and hold onto it better.
However, it is still true that our education system is still failing bit by bit, mainly due to our government and the lack of caring parents and teachers (don't get me wrong, they do exist). This is one reason I enjoy homeschooling - I'm being taught by people I trust, know, and I can see that they know what they're talking about.