The Current Evolution of Ancient Religious Institutions

[The Grand Nudger]

For primarily agrarian peasant society, high levels of literacy probably would bring little easily discernible benefit, and in the short term probably impoverish the society by removing parts of labor force from production to educate them at a time when child labor was critical to overall agrarian productivity.     On the other head, for society which dependent heavily on being the middleman in maritime commerce, high level of literacy would probably bring more easily discernible benefit.

In a primarily agrarian society one need look no further than agriculture for the cost of illiteracy and a lack of general education.  Then, or now, frankly.

There may be nearly a million minors working as field labor in the us alone to this very day.  We've observed 12 year olds in the fields, which, as it so happens, is when we suspect that field labor started back in the day.  As a consequence of demographic growth there are likely more children doing field labor today or at least within living memory than there were in most small nations in the 17th century.  Farm operations with high levels of minor labor are not particularly well known for their productivity.  Even less well known for productivity are farms operated by illiterates and/or people with no education whatsoever.  There are numerous federal and state prgrams aimed at this because it's seen as a driver of rural poverty as well as a loss of productive capacity and economic activity.  

If we, today, were to revert to a previous state -even more minors, even less education- say a pre 1950 state of us agriculture, then the loss would not just be economic or counted in bushels of corn per acre...it would be in human lives.  As we see, all throughout the history of agrarian societies, they struggled with this issue.  It's always been resolvable, but not by children who couldn't read, adults who saw no value in education, or people who were de facto or de jure prevented from educating themselves.  That's the very mountain we climbed over to realize better yields and better methodologies. To then communicate these methods and this knowledge from coast to coast. Not that we don't backslide. We've created another farm crisis in the here and now by telling all the smart farm kids to get off the farm for the last generation or two. That's how farms ended up being run by goobers who lost their shirts to agribusiness giants (while simultaneously destroying their land)..agribusiness giants who are very much interested in a well educated workforce and they seem to be doing extremely well on account of it.

In agronomic circles you'll often hear the medieval period referred to as the second green revolution (the assumption of ag being the first, the 1930's-50's being the third - and the fourth being some as yet undefined but always just on the horizon thing).  They were agricultural innovators.  Even in their own time they realized benefits through a more educated and technical agrarian workforce.  Without that there never could have been anything like the feudal system... and... arguably, with an even more educated and technical workforce it wouldn't have worked either.  In sum, imo, it is not and has never been that there would be a negligible benefit of education to agrarian societies, but that there would have been a negligible benefit or even a positive detriment to the authoritarian regimes those agrarian laborers worked the fields under.