Japan is facing a demographic time bomb because of their low birth rate. Since there are no immigrants, there are far fewer buyers to buy houses as time goes by. The opposite is true in the U.S., where uncontrolled immigration and a replacement birth rate is behind the strong demand for housing.
I have family in both Southern California and the Houston area and can show you what uncontrolled immigration and strong demand for housing does to more than a few neighborhoods.
Three families or 18 single men more into a house designed for one family. Formerly nice neighborhoods turn into third world slums. Real estate values plummet.
When we were married, my wife's parents lived in a nice but smallish house in a neat neighborhood 30 miles east of LA. They sold out in the mid-1990's and bought a house and lot at least double the size 30 miles further east with the proceeds of the sale. Until they retired three years later, they drove 60 miles to work one way! They were up at 4:30 a.m. and on the road by 5:15 a.m. to beat traffic. They got home about 7 in the evening for a quick supper and early trip to bed to start the same routine the next day.
My wife wanted to see the old neighborhood when we were there about five years ago. The old neighborhood was already starting to turn into a slum. She's had no desire to go back since.