Mead was close to writing a good article about the changes in speech, reading selection, and how literature reflects contemporary material cultures. She could have made a case for how cultural diffusion is a vital component of our own lives and that what we read at any given age will directly affect what is transmitted to the following generations. She could have done much more with this than to bemoan a contemporary adaptation of Greco-Roman mythology without acknowledging that it too is but one more link in the millennia of retellings and adaptations of certain story cycles to suit the needs of the considered literary/cultural generation. But yet she didn't and it is hard to parse "The Percy Jackson Problem" as being much more than a lament that doesn't hold up under much scrutiny.
I think Mead perhaps was thinking of cultural distortion, of how things are lost in the transmission of years and societies, but this wasn't the thrust of her argument. It just isn't a terribly profound piece (if it was ever meant to be construed as one). It would have been interesting to see a case being made for how the literature that children and young adults read today has been shaping their socio-cultural values. After all, what you read does matter. Look what The Jungle did a century ago. Then look how it is presented today and see the disconnect. Reading for "pleasure" can also mean reading what is socially acceptable, or at least the social interpretations of said literature. Reading for "pleasure" can also reinforce certain notions that help constrain generations. After all, when is "working class" literature ever presented as such during a reader's formative years? Yet there are many such titles that are read but not understood as such. Things have been distorted in the transmission and reading that incites, that provokes, that leads to personal rebellion is often neutered or shunted aside in favor of this notion of reading primarily for "pleasure."
This, of course, is a very different argument than the one Mead presents. It, too, is one that would anger many to even consider at all. But I think it would make for a more interesting and sustained argument about the vital importance of reading and how what one reads (and the whens and whys of that initial reading) can shape their world-views (and by extension, their very same worlds) than what was presented in Mead's article. Might write more on this topic at a later date.