Households does NOT equal people. You may have a multiple family household, owned by one family, but inhabited by several other, grown up children living with their parents (th eparents own the house, the children have a housing problem). A separate proble, is th ehomeless populaion that is not included in the household count. A still different problem is the quality of the housing
And of course affordability. To illustrate: my friends in NYC both have professional jobs, but they could not afford the a coop in which they live, if daddy did not shell some $100k for the downpayment. The Chronicle of Higher Educsation run an article few years ago that colleges in the Bay Area have problems recruiting faculty because of housing affordability - if a professor's salary is not enough to pay for the housing cost, something must be definitely wrong.
The insistence on single family dwelling, no matter how crappy but surrounded by an acre of lawn - makes the US housing "system" very costly and inefficient.
Wojtek