1) The investors that put money into a Broadway production are fine. Don't feel sorry for the investors. It was their risk to take, and one can only hope that they make informed decisions on how to invest their money.
2) Regarding the argument that Wildhorn shows are financially successful from cast album sales: that only applies to the composer, lyricist, producers and album producer. Investors of the show's production are normally not involved in the cast album financing.
3) After this latest failure, I wonder if the Broadway theatre owners will ever give him a house again?
"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