re: "It turns out that the American theater has no towering figure even attempting to lead it through this crisis, the way Andrew Lloyd Webber has in Britain. "
an orchestra can play music safely SO LONG AS THERE IS NOT AN AUDIENCE
And they're doing pieces for smaller ensembles, or chamber arrangements, or paring down from typical string sections. And spacing out the players in ways that would be difficult with an audience in the hall. I've heard a lot of concerts on BBC Radio 3, and they're all tossing out their planned programs to adapt.
(And that's another difficulty for US ensembles: weak national/regional broadcasting. Even if our ensembles could reprogram and assemble to suit applicable guidelines, most have no guaranteed broadcast outlet and would be on their own for the technical aspects. Few have an existing apparatus to reach an audience outside their hall.)