I was reading an article that casually dropped this paragraph:
If we are lucky, year over year, SARS-CoV-2 will evolve to cause milder disease than it has these past two years. That would be consistent with the virus that spread in 1918, which became the seasonal flu. It never again produced the same level of mortality as it did during its first two years, but the virus continues to evolve and kill hundreds of thousands of people every year. Most of us have come to accept this as inevitable.
Were seasonal flus not a thing prior to 1918? Did urban dwellers and other people in 1910, 1850, 1600 not head into winter half-expecting to catch the flu?