Can you please cite your source?
Check the reading level of any of the Federalist Papers and you will find that they were written on a postgraduate level. Do the same thing with most papers today and you will find the result to be much lower.
You are ignoring some very relevant facts:
1. The authors of the Fed Papers were not only the top intellectuals in the country, their paper was not designed to be read by the general populace, many of whom were illiterate. It was aimed at other intellectuals and governments.
2. Current newspapers are specifically written at a low education level to promote circulation. However, I would hazard that the general literacy rate, as well as the percentage of postgraduate literacy, is well above the American 18th century levels.
As far as education is concerned, I think the numbers of more educated people may be higher, but based on a percentage in comparison to the 18th century, I don't think we measure up. I will say there are MANY more in number and percentage who can barely read now because typically when you learned to read then, you learned to a greater level than what is required now to function in society. AND, of course we are talking about developed nations here.