Hm, you are probably right. My perspective is probably skewed. My grandparents built their own houses (altogether three, actually), my parents built their own house – and they really picked everything down to the “Which toilets should there be?” detail level.
Also, remember that not everyone owns their own house. Many people rent apartments or houses from other people, or live with families.
Between all of those factors, I would say a very small percentage of toilets in this country were picked out by the person using them.