Neat example. But The Music Man was set in 1912, when even Iowa bumpkins knew classical allusions and enjoyed chautauqua. And one must note that Miss Marion Paroo did NOT give in to the traveling salesman! No more "A's" for Hester :-)
Yes, but the movie came out in 1962 (the stage version a few years earlier) -- and the lyricist (Meredith Wilson, I believe) assumed that the 1962 audience would get the reference. He couldn't assume that today.