Did our ancestors not also die at an average age of like 28 tho
Only statistically, if you believe even that. Statistics are useful mainly for lying. If you include infant mortality, then sure, average age at death was something pretty low. If you exclude infant mortality, then they were possibly living longer than we do now.
No that is a common misunderstanding. In Athens, mean and median life length was 71.3 years (mean) and 70 years (median). The reason life expectancy was about 35 was because of high infant mortality. If half of infants die, then you have to average in all these 0's into the overall life expectancy. Modern medical science has wonderfully improved infant mortality. I cannot argue that. It is clear. But it has done very little for the rest of us. ... antibiotics (which will eventually fail) probably accouting for the rest.