I don't know if I agree with that or not.
Just as one example, my dad was diagnosed with high blood pressure when he was 17 years old. But there was nothing that could be done about it then, so he had high blood pressure for many years and died when he was fairly young because of all the damage he suffered before treatment was available. His mother never got treatment for her high blood pressure and died even younger.
Was he healthier than someone who has high blood pressure now?
Now you could argue, I suppose, that more people have high blood pressure now, but I don't know if that is true or not, either. For one thing, in my parents' day, people didn't go to the doctor nearly as often as they do now, so a lot of people went undiagnosed and untreated. For another, the definition of "high blood pressure" has changed over the years and with those changes, the percentage of the population with high blood pressure has changed, too.
Another example: I have asthma and have had the exact same symptoms since birth, but I was not officially diagnosed as asthmatic until I was 19 because the definition of asthma changed. As near as I can tell, I inherited the condition from my dad's mother (the same one who had high blood pressure) and there is evidence that asthma has been in her family line for generations. But not one of those people was ever actually diagnosed with asthma because people weren't back then. Statistically, of course, more people suffer from asthma now than they did in the past, but I wouldn't say that presents you with an accurate picture of asthma in previous generations.