Across America, the Covid-19 crisis is creating unsettling questions for opera companies. How can they produce performances during the pandemic? What kinds of art will people want? Will companies survive? To be sure, there have been other moments when opera has been disrupted and companies shuttered, such as World War II. Such circumstances always have the potential to change the genre’s trajectory. MIT Associate Professor Emily Richmond Pollock is closely attuned to these issues. Pollock is a music historian who studies how opera has evolved while keeping its links to…