The idea that population growth is essential to boost GDP, and that this is good for everyone, is ubiquitous and goes largely unchallenged. For example, according to the Treasury’s 2010 intergenerational report:
Economic growth will be supported by sound policies that support productivity, participation and population — the ‘3Ps’.
If one defines “economic growth” in the first place by saying that’s what happens when you have more and more people consuming, then obviously more and more people produce growth.
The fact that GDP, our main measure of growth, might be an utterly inadequate and inappropriate yardstick for our times remains a kooky idea to most economists, both in business and government.
Economists always, but always, distinguish between GDP and GDP per capita. Which neatly takes care of this particular whine.