I think a vaccine will be out by then; distribution is the major question mark. If a vaccine receives limited distribution by the end of this year, my guess is 15-20% of Americans will be vaccinated by April. By the end of summer, almost everyone who wants to be vaccinated will probably have done so considering ~30% of the country will not take the vaccine. It'll be a weird summer at the box office, but after no summer movie season this year, lower returns are better than nothing.