America’s Housing Affordability Crisis and the Decline of Housing Supply
Introduction
The decline of housing supply is the primary structural driver behind America’s current affordability crisis, according to comprehensive new research analyzing seven decades of national construction data. While public discourse often focuses on interest rates, demographic shifts, or post-pandemic supply chain disruptions, a rigorous analysis by Edward Glaeser and Joseph Gyourko reveals that the fundamental issue is a long-term contraction in the intensity of home production.
This deep-dive summary explores the evidence presented in their Brookings Papers on Economic Activity draft, detailing how the United States has transitioned from a nation of robust housing elasticity to one defined by regulatory constraint and production stagnation.Understanding the Structural Decline of Housing Supply
To grasp the severity of the current market, one must understand the historical baseline. The authors document that the decline of housing supply is not a recent phenomenon triggered solely by the Global Financial Crisis (GFC) or the pandemic; it is a multi-decade trend. In the 1950s and 1960s, the U.S. experienced a "golden age" of construction, with the national housing stock growing at approximately 4% annually.
Between 1950 and 1980, the nation added over 50 million homes. However, this growth rate dropped by more than one-third between the 1970s and the subsequent two decades. By the 2010s, annual housing stock growth had fallen to an anemic 0.64%, less than half the rate seen during the Nixon, Ford, and Carter eras.
This aggregate decline of housing supply masks significant regional heterogeneity that has only recently converged. Historically, Sunbelt markets like Atlanta, Dallas, Miami, and Phoenix served as elastic supply valves for the national market, absorbing demand through rapid construction. Twenty years ago, these regions were defined by high production rates compared to constrained coastal markets.
Today, that distinction has largely vanished. By the 2010s, building levels in key Sunbelt metros mirrored those of historically supply-constrained cities like Los Angeles or even declining industrial centers like Detroit. This convergence suggests that the decline of housing supply has become a ubiquitous national challenge rather than a localized coastal problem.
The Flattening Empirical Housing Supply Curve
A central contribution of this research is the concept of the "empirical housing supply curve," which measures the responsiveness of local construction to price signals within metropolitan areas. Ideally, higher prices should signal developers to build more units in high-demand neighborhoods.
However, the data shows a disturbing flattening of this relationship over time. In the overwhelming majority of large metropolitan areas, the tract-level correlation between price and housing growth was significantly lower between 2000 and 2020 than it was between 1970 and 1990.
This flattening indicates that markets are no longer effectively delivering housing where it is valued most. The decline of housing supply is particularly acute in desirable, high-value neighborhoods. While America once responded to demand by increasing density in attractive areas, it no longer does so consistently. Instead, construction has shifted toward lower-value tracts or ceased entirely in high-demand zones.
This misallocation implies substantial social losses, as the gap between what consumers value and what it costs to build continues to widen in the most economically productive regions.
Regulatory Barriers Driving the Decline of Housing Supply
If physical land scarcity were the sole cause of the decline of housing supply, we would expect to see consistent density caps across all markets. However, the evidence points strongly toward regulatory and political factors. The researchers utilized the Wharton Residential Land Use Regulatory Index (WRLURI) and found it reliably predicts the downward shift in supply elasticity.
Markets with stricter land use regulations have experienced a more pronounced decline of housing supply. Furthermore, the share of educated workers in a metropolitan area—a demographic often associated with greater political efficacy in opposing development—is also correlated with reduced supply responsiveness.
The paper invokes Mancur Olson’s theory of institutional sclerosis to explain this dynamic. As neighborhoods become more prosperous, incumbent residents ("insiders") increasingly leverage regulations to protect their property values and neighborhood character, effectively blocking new entrants.
This political economy perspective explains why the decline of housing supply correlates so strongly with rising prices and education levels. It is not merely that land is running out; it is that the permitting environment has become hostile to growth precisely in the areas where growth is most needed.
Ruling Out Alternative Explanations for the Decline of Housing Supply
Critics often attribute the decline of housing supply to labor shortages or rising material costs. The authors systematically address these alternatives. Real construction costs for an average-quality home have indeed risen by about 35% since 2000. However, in markets like Miami and Phoenix, housing prices rose by 184% and 107% respectively over the same period.
If construction costs were the dominant factor, price increases would track more closely with cost inflation. The massive divergence between prices and costs in these Sunbelt markets confirms that the decline of housing supply is driven primarily by artificial restrictions rather than pure input economics.
Similarly, while the GFC decimated the construction workforce, employment and establishments have rebounded in markets that remain relatively permissive, such as Dallas and Houston. If the industry lacked the capacity to build, these recoveries would be impossible.
Moreover, the remodeling sector has seen significant growth, suggesting that construction talent exists but has migrated to less regulated sectors. Therefore, the persistent decline of housing supply in major metros cannot be blamed solely on a lack of builders or materials; it is fundamentally a profitability issue caused by regulatory friction.
The Density Wall and Multifamily Construction
An important nuance in the decline of housing supply is the changing relationship between density and production. Historically, higher density was associated with slower single-family growth but faster multifamily growth. Recently, however, the negative correlation between density and single-family construction has weakened, while the positive correlation with overall housing growth has strengthened in some markets. This suggests that while single-family zoning remains a barrier, multifamily projects are becoming the primary vehicle for adding supply in denser areas.
Nevertheless, a "density wall" appears to exist in many suburbs. In Phoenix, for example, median tract density increased steadily until 2010 but has since stagnated. This plateau suggests that many communities have reached a regulatory or political limit on densification, contributing to the broader decline of housing supply.
Even when land is physically available, the inability to increase density in established neighborhoods prevents the market from accommodating new households without expanding outward into less desirable fringes or driving up prices in existing cores.
Price-to-Cost Ratios as Evidence of Supply Constraints
Perhaps the most damning evidence of the decline of housing supply is the widening gap between house prices and minimum profitable production costs (MPPC). In elastically supplied markets, prices should hover near the cost of construction plus land and normal profit.
Through the 1990s, Sunbelt markets like Phoenix fit this model, with few tracts priced significantly above MPPC. By 2023, however, nearly 30% of Phoenix tracts and over 40% of Miami tracts were priced more than 20% above production costs.
In Los Angeles, over 93% of tracts now exceed this threshold. This metric serves as a direct proxy for the impact of the decline of housing supply. When prices detach from costs, it signals that supply cannot expand to meet demand.
The fact that this detachment has spread from coastal elites to formerly affordable Sunbelt markets underscore the systemic nature of the crisis. Homebuyers are paying a premium not for better structures or land, but for the right to live in a jurisdiction that restricts its own decline of housing supply.
Conclusion
The research by Glaeser and Gyourko provides a definitive diagnosis of America's housing emergency: the decline of housing supply is a structural, nationwide failure rooted in decades of regulatory tightening and political resistance to growth.
While macroeconomic factors play a role, they cannot explain the magnitude of price appreciation relative to costs or the collapse of construction elasticity in historically pro-growth regions. Addressing this crisis requires acknowledging that the problem is not merely cyclical but deeply institutional.
For policymakers, researchers, and housing professionals, this document serves as an essential reference point. It moves the conversation beyond temporary fixes and demands a reckoning with the land use policies that govern American cities.
Only by reversing the decline of housing supply through meaningful regulatory reform can the nation hope to restore affordability and ensure that housing markets once again respond to the needs of their populations. The data is clear: without a restoration of supply elasticity, the affordability crisis will persist regardless of interest rate environments or demographic trends.