Indeed, it has always been the case that in order to have economic growth it is necessary to have more people.
In fact, not just no, but bollocks.
If economic growth were a matter of just having more people then there would be no rise in the size of the economy per capita, would there? And given that we do have economic growth per capita then ….well, you see the problem.
It\’s possible to make a weaker claim, that we can only have economic growth per capita if we have a growing population but that too is nonsense. The onward march of technology, our ability to add more value to resources over time will lead to continued economic growth.
There\’s just one special case where the assertion might be true: if population if falling faster than growth per capita is growing. Take a reasonable historical (for the capitalist world) average: 3% growth in GDP per capita over the years. If population is falling at 4% a year then total GDP will be falling while the living standards are rising. And as it\’s that latter that we care about, not the former, even in this special case we don\’t actually care.