An elementary school classmate of mine provides a more extreme case. He was a talented musician, the only person in our class who had seen a Broadway show, and one of the most outrageous musical queens I've known at any age. A hint, perhaps, but not proof. Many genres allow one to escape reality and vicariously enjoy the adventures of others, but nothing has the same stylish, witty, melodious fun that classic musicals do. Accessibility is a key issue here.
Musicals touch the widest possible audience, including many left cold by other narrative forms.
In the musical Les Miserables , Jean Valjean comes to life for millions who would never read Victor Hugo's ponderous novel. Grand opera and ballet are too big, too stylized to have the same effect. A good musical is the realm of human beings, while opera and ballet are all too often the realm of characters who belong to another species. Dolly, Tevya, Evita, Pippin, Annie, Curly, the Phantom and Norma Desmond are all terribly, wonderfully, and undeniably human. We recognize their feelings and in the process better understand ourselves.