> Those were all influenza A sub-types viruses which we've had experience with.

Let's be serious. Most doctors back then couldn't tell the flu from a coronavirus, and it was probably for the better.

You are taking the present-day degree of information and discounting it back at a much too generous rate.

People, even doctors, were all but alarmed in those years of flu epidemic, even though people died, and young people at that (the flu is a notorious killer of babies and young people)

They were not alarmed because in the great scheme of things nobody died. Most importantly nobody or almost nobody they knew died, so the process of extrapolation and panic didn't start, because those people perceived stuff which didn't happen in their circle of acquiantaces as not relevant to them, which is true even today, but we forgot about it.