Absolutely agreed on the dietary and other issues, and I think that largely ties into this point well. It wasn't survivorship bias because nearly all of the Ancient Greeks we know of would still have gone down in history whether they had died at 40 or at 80. But there is one major bias. Nearly all were upper class with ready access to the base necessities for a healthy life - clean food, clean water, basic sanitation (toilets/baths), and the ability to avoid the impacts of war.
I think you'll find that if you choose nearly to any comparable sample with similar access, near to regardless of the time era, you will again find life expectancy comparable to modern times. For instance here it is for the ten most famous Founding Fathers (data from GPT for convenience, so hallucinations are possible, but it matches up with my knowledge as well) :
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George Washington 67 Acute epiglottitis
Thomas Jefferson 83 Natural causes (suspected kidney disease)
John Adams 90 Natural causes
Benjamin Franklin 84 Pleurisy
James Madison 85 Congestive heart failure
Alexander Hamilton 47 Gunshot wound (duel)
John Jay 83 Stroke
James Monroe 73 Heart failure and tuberculosis
Samuel Adams 81 Tremor, possible Parkinson's disease
Patrick Henry 63 Stomach cancer
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The average age at death, excluding Alexander Hamilton, was 78.8, for people born from ~1700 to 1750! But yeah, like you mentioned - a major issue with is the masses at large were living in crowded unsanitary conditions while and eating/drinking unclean food, often while working dangerous jobs. So I think biasing our sample to the upper class of times past is quite beneficial because now a days even the poor have relatively widespread access to these 'luxuries', so we are more able to compare just life with and without modern medicine/knowledge.
I think you'll find that if you choose nearly to any comparable sample with similar access, near to regardless of the time era, you will again find life expectancy comparable to modern times. For instance here it is for the ten most famous Founding Fathers (data from GPT for convenience, so hallucinations are possible, but it matches up with my knowledge as well) :
---
George Washington 67 Acute epiglottitis
Thomas Jefferson 83 Natural causes (suspected kidney disease)
John Adams 90 Natural causes
Benjamin Franklin 84 Pleurisy
James Madison 85 Congestive heart failure
Alexander Hamilton 47 Gunshot wound (duel)
John Jay 83 Stroke
James Monroe 73 Heart failure and tuberculosis
Samuel Adams 81 Tremor, possible Parkinson's disease
Patrick Henry 63 Stomach cancer
---
The average age at death, excluding Alexander Hamilton, was 78.8, for people born from ~1700 to 1750! But yeah, like you mentioned - a major issue with is the masses at large were living in crowded unsanitary conditions while and eating/drinking unclean food, often while working dangerous jobs. So I think biasing our sample to the upper class of times past is quite beneficial because now a days even the poor have relatively widespread access to these 'luxuries', so we are more able to compare just life with and without modern medicine/knowledge.