One of the very sad things in history is the trajectory of formerly disempowered groups who, upon attaining greater social power, briefly pass through a phase of eagerly embracing self-betterment only for the group then to adopt norms that militate against self-improvement. When we look at the experiences of freed slaves in the USA and the working class in Britain we see the pattern clearly: lending libraries and other resources enabled literacy to rise dramatically over the 20+ years following emancipation for both groups. Thereafter, however, proletarian norms were adopted by both groups and among these norms was the idea that self-improvement was a “betrayal” of one’s fellows. Thus even today African-Americans scorn and ostracize their peers who attempt to achieve an adequate education, and British working-class adults do likewise to any child who exhibits a desire to pursue academic achievement.

As is so very often the case, group norms impose unnecessary and lasting self-harm.

It’s nice that fan fiction has encouraged a generation to exercise its creativity and thereby improve both their reading and composition skills; it’s sad that this phenomenon has been, as you correctly note, largely confined to middle-class and upper-middle-class adolescents.