I hear what your saying but can't you use the same logic with bathrooms? Sure, we could all get by with 1 bathroom. Hell, we can get by with just communal bathrooms. But it turns out it's nice to have the luxury of not sharing things, even with your family. It's nice to be able to customize things the way you want. I will buy the argument that people will give up personal car ownership when I start to see people give up having personal bathrooms.