Why do commercial and residential apartments rarely have exposed bathrooms?

Due to the nature of land with 40-year property rights, some attributes of commercial and residential properties cannot be changed. For example, commercial and residential buildings are as big as office buildings and hotel apartments. They are all block buildings with no transparency from north to south. Except for corner units, other types of units, especially middle units, have only one window and one side of lighting. Most developers When designing a house, the only window will be reserved for the living room or bedroom, so it is difficult for the bathroom and kitchen to be clearly visible.