Between 1890 and 1930, the number of housing units in the United States grew from about 10 million to about 30 million; the pace of homebuilding was particularly brisk during the economic boom of the 1920s.
For example, if some market participants recognize the presence of a bubble but do not know how common their knowledge is, they might reasonably expect to make the most profits by riding the bubble for as long as possible, with the goal of trying to sell the asset just before it collapses.