Ignoring the argument around whether showing up before the population density is high confers some special “native-ness” and ownership (which I think would need to be fleshed out significantly to be really compelling), the math doesn’t really make sense.

Typically people’s lifetimes overlap their kids’ significantly. I mean most people meet their grandparents, so if you have a fertility rate of 1, and an area becomes attractive to early-career people who are just settling down and starting families, and the existing housing become taken up by that group, then I guess the area will have to house the original population, plus their kids, plus their grandkids, so we’ll need housing for 175% of the original population, total.

Of course the area is, by not accepting new immigrants to get back to replacement rate, setting itself up for long-term unpleasantness as the tax base ages into retirement. But hey I guess that’s their right…