Aren’t the backstreets of the less central ku filled with houses? I mean Setagaya, Ota, Edogawa, Adachi, Suginami, etc.
I used to pick stations at random to arrive at and explore, and what I always saw was endless houses. Only the areas closer to bigger stations had manshon.
I think you might be conflating Shibuya/Roppongi/Shinjuku with less central parts of the 23 special wards.