I would say that's because the type of education was still the same.
current education in the US is based on the Prussian system: one person dictating to a larger group of students, standardized tests, and so on.
studies typically show that boys learn better in small groups that are competitive
there'sno reason that it wouldn't "seperate, but equal" and be different. In an ideal environment, girls would not be as successful in a boys class, as boys are not as successful in a girls class, bt both classes maximize the ahcievement of the individual sexes