Trust me, the complications would still be awful. There is no treatment for blindness for example. I've been practising medicine since 1982 and have seen exactly TWO cases of measels, one when I was a med student and the peds attending called us all in because "we may never see this again".
We DON'T want to go back to the days before the vaccine was common.
I had Scarlet fever as a child in the 50s. I don't know of anyone who's had this disease in at least 20 years. Do kids get it anymore? If not, why not? I don't recall my son getting a vaccine against it, but I could have forgotten.