This doesn’t suggest anything has changed over time. Even if ineffective medications somehow lead to infections, we have no reason to think this tendency to prescribe ineffective medications has increased over time.

But why might people have a higher rate of serious infections today despite better health? This answer doesn’t help answer that question.

If most serious infections are now curable, why is the rate of serious infection going up? This answer makes the discrepancy more difficult to explain.

A proportional increase in the number of infections doesn’t change the rate of infection in the population. Rate of infection involves a measure of number of infections divided by the population. The stimulus says the rate of serious infection has increased.

This is a reason the rate of serious infection might be higher today despite the increase in life span and overall health. Modern treatments, as they are used in a higher proportion of people over time, increases susceptibility to infection, leading to a higher rate of infection.