I have done considerable study into local history in my rural Third World village, via genealogical data I get via the Web from Salt Lake City.
At one point, I discovered a nearby county (municipio) apparently had a population around 5,000 (based on 250 births when the birth rate was usually 50 per year per 1000 population) and in the 1870’s, one year had nearly 200 small pox deaths.
The average age at death that year came out to around 8 years old. Which is not the same as average life expectancy, unless it continues a long time.
Yet, there were several people who lived into their 90’s.
Most of those small pox deaths were younger than 3 years old. Apparently, they had an epidemic every 3 or 4 years, and those who survived were immune. They did have one women in her 20’s who died of small pox, which meant somehow she had escaped all the other epidemics. The epidemic would come only when there were enough new babies who weren’t immune, and as soon as they died or got immunity, the epidemic would die out for several more years.
The sad part was small pox vaccine (an extract of cow pox) was already in use in other nations.
As far as difficulty in getting good medical care, most of it involves the very rare smart doctor, not the hospital nor testing facilities. And, that smart doctor is as likely or unlikely in rural Alabama as in NYC.
My SIL told about a friend who had been in very bad health for several years, and was expected to die. With all kinds of testing, no one came up with any idea what the problem was. Finally, someone got him to go to Anderson’s in Houston. He came dragging in, looking bad. A young doctor came bounding up to talk to him before he could even register.
In a minute, several other doctors were there, all excited, talking to him, asking him about his problems. Right there, before he registered or had any tests, they figured out what his problem was.