Megaplexes will never die off - because streaming will never provide these big studios with the money they need. Not unless we part ways with the big special effects blockbusters. And we won't. Only way that could conceivably be profitable is if every studio has their own streaming service - and people are already grumbling about their being too many of those now and missing the days where everything was just on one service, Netflix. I don't even know why people are trying to argue that theaters are a bad thing and the future must be that everything starts out as streaming.
Look, if you're in America like me, we're not going to be able to go to the theater responsibly until next year probably. And some theaters and chains aren't going to survive. But it is inevitable that once we are able to do so safely people will start flocking to the theaters to see the next big MCU movie. The theater is not going to die out forever. It'll survive Corona, it will make a comeback, and ultimately isn't that a good thing?