It's not about that plant extract are not effective, the only drawback to use medicine with plants is the dosage which may be very variable, depending on the harvest time. But this is mostly only relevant in very toxic substances. That people live longer as in the past is a myth, because it always depended on the life standart of the person. In feudal times the normal people with a bad alimentation and hard work in dangerous times, naturally didn't get old. But between the elite ages over 80 years are not so strange. Other influence are also the high quote of the death of newborns, also the advances in the medical treatments are important, less the medicines used. Even today eg.miners in coal mines often do not even reach retirement age, also those who live a life of stress and worries, with poor quality food, can have a heart attack at 40. Allergies, diabetes, circulatory problems, morbid obesity, some cancer, are mostly caused by the excess of additives in food, observed especially in the USA, where it is very common for the industry to disguise poor quality and contents with additives and chemicals that are banned in most other countries.