> fertility back up to 3 ... it's too late And using immigration to fix the population pyramid in the USA would probably not work due to housing and politics?

> fertility back up to 3 ... it's too late And using immigration to fix the population pyramid in the USA would probably not work due to housing and politics? New Zealand fixes its birth rate imbalance somewhat by immigration. About 30% of our population was born in another country (i.e our population is 50% higher than it would be without immigrants). Note that NZ is managing to make more houses "Auckland increased housing supply by 4% from 2016 to 2021"[1]. Interestingly increases in house supply don't decrease prices (presumably house demand is still outstripping house supply in New Zealand, unlike some other aging population countries with declining house prices in locations). Auckland is highly unaffordable (about as relatively unaffordable as San Francisco: wages to prices). Immigration drives house prices up, simplistically +10% immigrants doubles or triples house prices: "We suspect these two features largely underpin Coleman and Landon-Lane's (2007) and McDonald's (2013)| macro estimates that a 1 percent population increase from migration is associated with about a 10 percent increase in house prices nationally"[2]. [1] https://worksinprogress.co/issue/upzoning-new-zealand/ https://worksinprogress.co/issue/upzoning-new-zealand/ [2] https://motu-www.motu.org.nz/wpapers/19_14.pdf https://motu-www.motu.org.nz/wpapers/19_14.pdf