I grew up (as the oldest of 5 siblings) in a split-level home about 1200 sqft. It was fine, we just shared bedrooms. Based only on anecdotal evidence, we grew up closer than other families I knew where each kid has their own bed and bathroom.
Well it’s time to rethink that then. Necessity is the mother of all invention, and at one point it’ll be a necessity to downsize if you want an affordable home.