The lower middle classes can't afford a house/apartment in places with laws that make it difficult to build new houses or apartments, including many places with lots of tech jobs. But in rural areas, or many Midwestern cities, or much of the Sunbelt, a house is still very much within reach. But many of the most productive regions of the country are zoned such that very little new housing is built, and rising incomes for some just mean more competition for existing housing.