Less plastics in everything is the big difference, IMO. Even a can of beans is lined with some sort of plastic film.
My father-in-law was a fireman and was in anything from 10-15 fires/month from 1965-1975, most of that time in a rescue company where he would pull people out, without an oxygen mask because they didn't fit. He did it enough that his knees were shot. He smoked as well, and in now in his 80s, along with a big cohort of his buds.
My brother-in-laws on both sides of the family are in fire service, and I've been to several funerals for guys in their 30s and 40s, who probably see 3-5 fires a year, are mostly fitness buffs and don't smoke. All for stuff like bladder cancer, esophageal cancer, etc. I know one of the theories is around fire protection gear causing carcinogens to be absorbed through sweat, and another issue is the toxic stew that is found in car or house fire smoke.
Another factor to consider, newer houses are sealed up with poor ventilation and build quality. Your typical >1985 home is largely assembled with glue and don't ventilate well and tend to have alot of mold. My house is a circa 1920 average quality single family. It ventilates well in the summer, has few materials hazards other than some lead risk, etc.