Soup and Beer -
Well to be fair, they had no competition since theaters were closed. And with schools out and everyone getting cabin fever it was the perfect environment to generate that kind of profit. As expensive as it is, there are many who still want the theater experience. That doesn't mean the theater business will survive though even after a vaccine is found.
What are ways for theaters to survive? Theaters can't be their own content makers or is it content-makers can't have their own theaters, but the streaming-content model bypasses that.
They may very well be like bookstores. The content will still be produced, but the specific store to sell them may or may not be around.
Not an apples-to-apples comparison, as other than wait time (i.e. - buying a book at a store today vs ordering it online and waiting for it to show up), the end experience is the same.
Going to a theater vs watching it at home isn't just about consuming the content - it's the experience the surrounds it.
For some, the experience is better at home because you don't have to go anywhere, you don't have to deal with loud people, etc.
For others, the experience is better at the theater because of the technology.
Pricing is also a huge factor. People are willing (have been conditioned?) to pay more at the theater because they know they're paying for the experience and not just the movie. On the other hand, paying $20 for a temporary rental of a new movie just to watch at home is a bit of a kick to the nuts compared to prices of similar content.