The "roaring 20's" all can be traced back to the 1918-1920 Pandemic and the original World War. Much like now, people had to change how they lived and wore cloth masks just like all of us are having to do. After that came the rise of the Speakeasy to get around prohibition laws. The 1920's bacame known as "the roaring 20's" because people were back from the war and the Pandemic was over which meant it was time to party. That's sort of what I imagine happening once we have a widely available vaccine.
People want to get out and do things. People want to go conventions, concerts, sporting events. I think people will get over crowds a lot quicker than you'd think.