There was no magic longevity potion those of means had. All they had over the common class are the things we all have and take for granted today - protection from the consequences war and mostly stable access to clean food and water. The upper class of times back then arguably less so on both accounts than even a lower class individual today. This was the whole point. It's not like you could attribute their longevity to sophisticated medicine, because it literally did not exist at the time.