The simple dull reality is that there's a huge shortage of homes because homes were under built for decades and decades due to 1) exclusionary zoning and 2) governments stopping funding any and all below market housing in the 1990s.
The shortage of suitable homes of course hurts families very badly.
Many large homes suitable for families are occupied by retirees that don't want to move and don't have anywhere good to move (because again, we've built little). Zoning prohibits subdivision and redevelopment of the vast majority of the surface areas of cities so creating more housing is difficult.
Families need 1300sqft+. We badly need to rezone the entirety of our cities broadly to allow massive sfh lots to be redeveloped to create multiple 1300sqft+ spaces suitable for families. Rowhouses, Townhouses, and Apartments.
Canada is just beginning to roll out $10/day daycare, which should reign in a lot of these costs and make it more affordable to have a family. It'll be interesting to see where Canada's growth rate is at 10, 20 years from now once that is common.
Of course other costs elsewhere (ie. housing!) have spiked so much that will further discourage household growth, so more work needs to be done.