China's one-child policy is estimated to have made the world population 400 million people smaller than it would have been otherwise. Using data over the period on the amount of economic growth per additional person, Marin Tupy and Gale Pooley estimate that
...global resource abundance would have increased by 1,118 percent (rather than 609 percent).
More people makes the world better. If authoritarian rulers had not adopted the one-child policy, we all might have been twice as wealthy (on average) right now.
I recommend giving the entire article a read. Their methodology is the best one can do with counterfactual speculation, meaning that there could be significant variation in what may have actually occurred, but it nonetheless is a compelling example of how population growth can often increase wealth.