This article is terrible. It starts off talking about high vacancy rates for commercial properties, then segues to talking about housing shortages. Vacancy rates for housing is definitely not in the 27% range implied by the article. They're in the single digits, with the hottest housing markets also having the lowest rates.

https://www.census.gov/housing/hvs/current/index.html

https://www.census.gov/housing/hvs/data/rates.html

Sorting by the census areas with the highest rates gets you areas like Jacksonville, FL, Baton Rouge, LA, and San Antonio-New Braunfels, TX. Superstar cities like SF and NY have rental vacancy rates of 5.5 and 5.4 respectively.