
A quick look at this map shows the biggest metro areas tend not to have a surplus while smaller regions have a higher likelihood of having a surplus. There is additional analysis showing at least a few metro areas that had a housing surplus in 2012 that did not in 2019.
While it is intriguing to see that some places have housing while others need it, the answer is not to have people in large numbers move from the housing shortage areas to those with a housing surplus. Both the rise of certain cities in recent years and the COVID-19 pandemic offered some hints of what this leads to: the effects of cities losing residents (if just temporarily) and rising housing prices in markets experiencing a lot more interested housing seekers. At the same time, as noted in the article, a national policy is difficult to imagine and/or enact.
Hopefully, by the time a similar time period passes and a new map is released, there are more metro areas with available housing.