jpbran said: "Then why are so many shows still selling tickets for the following week? (not being combative, just trying to understand the thinking)"
Insurance. If they stop selling tickets for dates that have not yet been cancelled due to the government-mandated closure, whatever insurance they may be receiving (if any) would come to an end.
Theatrefanboy1 said: "It wouldn’t surprise me if some of the long running shows maybe started up sooner say in September to test the new approaches and then slowly having others added. As well we know that most of the shows that were still in previews will likely have another 4-6 week rehearsals and tech runs. Before. So if phantom is selling now for December I’d say the rest would follow after that."
If the government tells them they can't open, then they can't open. At this point, once the all clear is given, it would probably be weeks before we see any performances. Aside from the technical and mechanical aspects decaying for months, and union demands demands for a safe-opening, there are other practical considerations, chief among them the availability of the various casts and crew. Certainly there are actors who would not be returning for various reasons, the number of which may affect a show's ability to reopen quickly.
Until social distancing is relaxed or eliminated, Broadway is closed.