Solution should be to make mortgages assumable. Won’t happen, though.
Also d/k why you need a huge house to breed sprogs. Under 1000 sf was average till the mid-60ies, and people had more kids then than now in the US. In short, the prices of McHouses out in Outer Lizardia will plummet, and I’ll laugh at the rubes who bought there and are now trying to sell.
