At the High School of the Performing Arts depicted in Fame (and, I am sure, at such high schools in real life), the students spend only about half their class time developing their artistic talents. They spend the other half studying more academic subjects – math, science, history, English.
At Rowling’s Hogwarts School, on the other hand . . . although the students are put through very intensive courses, they appear to study absolutely nothing that is unrelated to magic – with the arguable exception of “Astronomy,” and somehow I doubt that course includes any astrophysics. All the students were literate by the time they arrived for their first year at Hogwarts, so they must have been through some kind of general primary education that covered the three Rs. But at Hogwarts . . . well, the graduates may know all about divination, charms, potions, and defense against the dark arts. But what do they know about Newton’s laws of physics, the Pythagorean theorem, the periodic table of elements, Plato’s philosophy, the Romantic period in English poetry, or the Peace of Westphalia?
Rowling’s wizards live in a self-contained underground society and rarely pay more attention than necessary to Muggles and their ways and their events and their vast store of non-magical knowledge. Are they foolishly depriving themselves? Could their society not benefit from such Muggle learning?
And how self-contained can their society really be, anyway? We know the food at Hogwarts dinners does not just appear on the tables magically, it is prepared by the school’s house-elves – but where do the elves get the raw ingredients? Some wizards are in the business of growing herbs for magical uses, but there does not appear to be any such thing as a wizard farmer who simply grows food for market. It would appear all wizards buy their food, ultimately, from Muggle farmers – which means wizards, or perhaps just a few specialized wizard grocery companies, must have some mechanisms in place for discreetly converting wizard currency into Muggle currency. Which means what happens in the Muggle world does affect them, after all, in some ways – instability in Muggle food markets would also affect the price wizards have to pay for their food. And it is probably the same for a wide range of commonplace products and commodities wizards use but do not make. And then there are Muggle wars, which are bound to have some disruptive effect even on the wizards’ world. So isn’t Muggle knowledge something they sometimes really need?