A vacant 2 bed room 1 bath house in Mansfield Ohio does not help the family of 5 in San Francisco let alone Cleveland. Where the vacancy is and the “quality” so to speak matters a lot.

Additionally, some percentage of homes have to be vacant to allow someone to move into it. You will need to provide evidence that the vacancy rate of a specific market is causing prices to go higher. Citing national statistics when talking about a local issue does not help.