The fic isn't about how the muggle world would change Rowling's HP world (such a misconception would tend to create a negative opinion regardless of whether that opinion was accurate or not). So instead I will comment on the topic at hand.
I don't think we should assume that people in a D&D world choose their class advancement with anywhere enough ease that it would take for us to assume our own class advancement. I remain convinced that it is more plausible to find and assist and existent caster than it is to claim we would be a caster.