The actors on Broadway did it live every night for years, including with stand-ins and fill-ins. It’s a pretty magical piece, for sure, and one of the first “raps” ever in popular culture, I believe.
Music Man was Meredith Willson’s biggest hit (he also wrote “The Unsinkable Molly Brown”), and there’s a book detailing the drawn out process of having written the piece called “But He Doesn’t Know The Territory” which by coincidence I just finished reading.
The play was originally sold to CBS for $100,000 but dropped after nobody could agree on casting. It gestated for another long period of time before finally appearing on Broadway, a triumph which surprised most everyone, who saw it flog and fail on the road in multiple houses. Just shows you…
It was the stubborn desire to experiment with rhythmic, rhymeless, speak-song that finally got me to select a typewriter key one weary day and punch it. The result three weeks later was a brand-new first scene involving a bunch of salesmen on a train, speaking an opening number instead of singing it. Their words were pure dialogue, with no melody and no rhyme. The effect was song, though, because of the underlying rhythm—the rhythm of the train. While I was at it, besides establishing the 1912 period and something about its characteristics, I sneaked into this opening speak-song considerable exposition—often a painful part of a play because of the latecomers stepping all over you while you’re trying to find out what’s going on.
The book is not really that interesting, a lot of “writing for writing’s sake”, but it was a pleasurable jaunt into one of my favorite musicals of all time.