Finland's median household income per capita is higher than the European average despite having much lower birth rates, and lower rates of immigration than the European average, while S. Korea, and Japan are at the top of the list for Asia's median household income per capita despite having lower birth rates, and lower rates of immigration than a lot of Asia.
Explanation??
Stop being coy, big guy. YOU tell US. Then we can scrutinize your claims.
Bottom-line is that there seems to be little difference between huge immigrant societies, and low immigrant societies in their income per person.
His theory, and a common theory by multiculturalists is that we need more young people working in the economy to propel the economy, and therefor immigration will fill such a gap.
This seems to be a terribly narrow, and simple view, however.
Having more kids, and younger adults in an economy might drive more GDP into the economy, but having more kids might also split the income between more people, thus watering down the wealth, it also would presumably put more pressures on the system to pay for kids schooling, or their prison sentences since young adults get into more trouble than their much older counterparts.
So, absolutely I don't see much of a win by having more kids, and young adults in an economy.