What happens when an adult child moves back in with their parents? They have "gone without" one unit of housing.
What happens when three friends move in together? They have collectively "gone without two" of the three units of housing that they would have otherwise have occupied.
Conversely, what happens when my wife kicks me out because I spend too much time on Hacker News? I am now looking for new housing.
In each case, the number of people remains fixed, but the demand for housing has changed. Price will definitely affect what strategy people adopt: whether to live alone or share with friends or whether to live in a cramped apartment or in a 3 bedroom house.
To first approximation, everyone needs a place to live,* but there is more elasticity in the amount housing each individual consumes than is commonly believed.
*I have known several people who have deliberately gone without housing entirely for a time in order to save money.