Anyone saying, "hey, injuries happen all the time, it happened in Little Mermaid, and Xanadu" are missing the point at a monumental level.
Whether it's fair or not, Spider-Man is now famous for being an out of control, dangerous production. This is Spider-Man's claim to fame. When Conan performs parodies of it, he has set pieces falling on the performers. When my family was visiting this weekend, they would joke, "well, we could see Spider-Man, but I'm afraid something will fall on us."
Even if this actor is not hurt (which we all pray is the case), I predict this show closes down.
Behind the fake tinsel of Broadway is real tinsel.