It's not just Hamilton.
Musicals have always had a built-in advantage as cultural products. Individual songs can translate and build interest via cast albums or Tony telecasts in a way that's very difficult for plays to emulate. A lot of kids grow up on musicals like Grease and Annie -- and, yes, now Hamilton — while early introductions to plays, however great, might make them seem impenetrable or like homework. (I'm looking at you, William Shakespeare, and doing so lovingly.)