The Theatre DEVELOPMENT Fund often has tickets available to new shows that open in a season, which often includes shows like the below mentioned, as they haven't yet "taken off."
Or, shows show up on TDF because it's a poor sales month.
Or, shows show up on TDF because they have had their hayday and are now losing life.
Thus helping to extend the life of a show, whether it be a horrendous show or a Pulitzer Prize-winning show.
"The Spectacle has, indeed, an emotional attraction of its own, but, of all the parts, it is the least artistic, and connected least with the art of poetry. For the power of Tragedy, we may be sure, is felt even apart from representation and actors. Besides, the production of spectacular effects depends more on the art of the stage machinist than on that of the poet."
--Aristotle