To expand a bit on the excellent points that Singingbackup has made, broadway shows depend on backers. More often than not, these backers are individuals or corporations who are less interested in "art" than in making a healthy return on their investment. They are more likely to finance something they consider reasonably "safe," that is, something that will appeal to the broadest audience possible, than risking losing their investment on something that's non-formulaic or cutting edge. Remember, Broadway shows don't have commercials inserted (except in the Playbills) or tax dollars behind them. It's very true that many of the most creative and artistic shows begin life Off or Off-Off Broadway, and in regional or even smaller venues. Show Business is exactly that, a business driven by the need to make a profit in order to continue at all, just like any other business. If Broadway theatres were filled with cutting-edge shows that were artistic, but appealed to a very narrow audience, there would be fewer people attending, the profit margin would diminish, people would be less willing to invest, and eventually it would close up shop entirely.
"And the postman sighed as he scratched his head, you really rather thought she ought to be dead..."
