It can be both. Median price of a home is $400k. Homebuyers need household income of ~$117k to afford typical home in U.S. Their income from ther visa enables their buying power to compete against citizens. About 300k H-1B visa holders own homes in the US per FWD.US. Other comments in this thread speak to the wage suppression and lower wages.
https://www.bankrate.com/real-estate/home-affordability-in-c...