Doomsday, the catch is in the “among reported cases” phrase. They didn’t put that in for no reason. Unlike today, when anyone who suspects his child has measles will go straight to the pediatrician’s office, then not everyone went to the doctor. They kept their kids as comfortable as possible and hoped for the best. I would also imagine that in that scenario, if a kid came down with pneumonia as a result of the measles and ch”v died, the cause of death would be listed as pneumonia – not measles. Same for encephalitis.
As for concern, of course people were concerned. There just wasn’t much they could do about it before vaccines came along. Same for tuberculosis and mumps. And cut fingers before penicillin. You did what you could and hoped you’d be on the bright side of the statistics.
And your car example doesn’t work. The world is very concerned about car accidents. That’s why we have so many road safety rules: Because the road is a very dangerous place and we have to do whatever we can to keep it as safe as possible. Neither you nor any of us on this thread (I would assume) ever lived in a world where measles, mumps, rubella, smallpox, polio etc. were a fact of life. If you had, you might feel differently about vaccines.