Religous Economists

Behavioural economics is about improving economics. But why do we want to improve economics? Why is economics important?

Tomas Sedlacek in The Economics of Good and Evil: The Quest for Economic Meaning from Gilgamesh to Wall Street (my current bedtime reading) provides the following answer:

"a strong faith in the beneficial effect of material progress is professed by a majority of the key figures of economic thought of our time. This why we must constantly grow, because we (deep down and often implicitly) believe that we are headed toward an (economic) paradise on Earth. Because care for the soul has been replaced by care for external things... economists have become key figures of great importance in our time... They are expected to perform interpretations of reality, give prophetic services (macroeconomic forecasts), reshape reality (mitigate the impacts of the crisis, speed up growth), and, in the long run, provide leadership on the way to the promised land - paradise on Earth."

(p.49)

I am struggling to find good reasons why this might not be true...