During Wave Four the federal government became a front-stage actor in a still predominantly private housing market. Washington held the keys to a comprehensive system of mortgage insurance and eagerly-sought-after subsidies. Both systems were administered through an elaborate administrative structure, spearheaded after 1965 by a separate Cabinet department. Wave Four carried into the Nixon and succeeding administrations, to their manifest discomfort; there were energetic efforts, only partly successful, to reverse or revise policy. By the end of the 1970s Wave Four had lost momentum (the 26-million unit goal falling short by a considerable margin), and not long thereafter was in full retreat. Production subsidies were largely replaced by family subsidies and new construction supplanted by rehabilitation. The appetite for expensive ventures had diminished. The first eight years of the 1980s were to pass before another housing authorization law was enacted.

Forces are now converging to generate a fifth wave, galvanized by the plight of the new homeless, a phenomenon that has pushed housing up near the top of the public agenda with an urgency not observed since the demobilization years right after World War II. The fifth-wave movement is reinforced by the discontents of a younger generation of middle-class housing have-nots, who aspire to, but infrequently obtain, a level of housing consumption equal to that of their parents, who had done so much better than their parents.