Agglomeration effects might change the YIMBY calculus
Implicit in this analysis is that density is valuable, and we can create value by increasing the densities of our cities. They consider the possibility that the increase in property values due to an increase in density may outpace the decay in property values due to an increase in housing supply. This is possible in a single metro, since population is highly dynamic and new residents can come from other cities and states, but if federal policies caused  a universal increase in metro density, the relatively static population at the national scale would prevent the decay in property values from being wiped out by the agglomeration effect. You can imagine everyone moving a quarter mile closer to the closest metro population center. Average density and thus value would increase, while costs would stay constant.<p>I heard of a study some time ago that said that restrictions on urban development have cost the American economy on the order of trillions of dollars over the past few decades. When you also consider that existing property owners in cities have an incentive to maintain or increase their property values by limiting new construction, there is a powerful argument for the federal government to act on behalf of the interests of the nation as a whole in having more dense, dynamic, inclusive urban centers and prevent cities from enacting anti-development policies.<p>Furthermore, while developers are typically scorned by my comrades on the left, such a policy would be progressive in that it would tend to reduce the wealth of rich property owners, while decreasing costs for renters and making cities more accessible to people with fewer resources.