It doesn't matter how much the show costs as long as it WORKS. There are directors that can make it work by miming props, clothing the actors in all-blacks, and using a bare stage with minimal lights. There are directors who can collaborate with designers and get fancy-schmancy sets/costumes/props/effects and make it be just as effective. Different, but both can work in their own way.
Spectacle is ALWAYS involved with theatre. The musical genre is a spectacle in itself!! The orchestra is a spectacle factor, the music is a spectacle factor, the singing and dancing are spectacle components, too! *gasp*
In the case of SPIDER-MAN, the producers think they can get their money back best by going with eye candy -- the pyrotechnics, flying, aerial stunts, etc. And I happen to agree that this is the best way to get their money back. Broadway is commercial theatre (minus the not-for-profit companies).
"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