Scientific progress is typically the result of outliers at the upper end of the normal distribution which doesn't inherently contradict a decrease in average knowledge. (i.e. a larger standard deviation could overcome a lower average)

Consider nutrition. Technological advancements mean that people have access to both higher-quality food and lower-quality food than their ancestors. In practice that seems to have resulted in some people eating healthier than their ancestors could have, and others worse.

We have one of the most incredible vaccine technologies in mRNA and yet vaccination rates are going down.

We have the best medicines we’ve ever had, and yet life expectancy is down in many countries.

We have more wealth as a globe and yet we are fighting more wars than in generations.

We have more automation than ever and yet people are working harder for less.

We have more capability for democratization of knowledge and capital and yet inequality is higher than ever.

The list goes on. Technology/science are not ends in themselves, and the positive ends they allow are going in reverse.