Jordan Catalano said: "What I’m most curious about now is when shows will stop testing cast/crew."
I think cast testing is here to stay as long as about half the cases are symptomatic. Maybe it eventually goes down to 1x a week if there haven't been Covid cases in the company for X amount of time. Testing is data that can inform decisions. In any situation, management wants to know why actors are out sick (bronchitis or stomach flu that can spread will be different than an injury received at work, or vocal fatigue, or a mental-health day, or something else) so they can be prepared for possible future illnesses and schedule additional rehearsals/fittings as needed.
The outdated belief of "actors should go on even when sick" has, sensibly, become more of an "actors should be careful not to hurt themselves further by performing while ill" situation, even before Covid. Mainly for musicals –– Amber Gray could conceivably go on in Macbeth with the sniffles or a cough; if she were in Hadestown, that could negatively impact her vocal performance.