Earlier quoted context omitted.
Development and economic growth. In the Roman Empire, people lived 30 years and died. Most were illiterate. As a society develops, and has more excess resources, allocating more and more of those resources on keeping people alive, healthy, and educated seems reasonable. What's missing from the charts is quality. We spend a lot on healthcare, but we also now have multi-million-dollar MRIs machines and similar magic.
What you said is WILDLY wrong. People in Roman empire lived until 90 just like us. For example Seneca de Elder was 92 when he died. The reason why "life expectance" was 30 years was because child deaths, since that number is just an average. If you have 2 people living in a country, one is 100, and the other is 0, and the child dies, life expectancy is 50.
not too bad.