Jesus Reddit, stop hating economic growth just because you don't understand it.

Unbounded economic growth is possible even in a world with static resources available.

Economic growth happens when we do more things, or build more things, for each other.

New techniques and innovation constantly allow us to do more with less.

The sentence "Wealthy countries can create prosperity while using less materials and energy" is true - you don't even need to append "if they abandon economic growth as an objective." onto the end of the sentence. The sentence is true without it - in fact, adding it is misleading because when you add it, the sentence insinuates that it cannot be done without abandoning that objective, which is simply not true.