I thought living rooms and dining rooms were replaced by ‘great rooms’ years ago. The article must be talking about real, sizable homes that still have those formal rooms, not typical new family homes.
My house was built in 1972. It has a formal living room that we never use and a dining room that we use two days a year. If I built another house I would never have eithe rof these in the floor plan. I would have a media room though with a 50+ inch TV and surround sound.
I also would have a three car garage.