Where I live in Southern California the problem is that supply is kept down by people renting out their first home and buying a 2nd. The houses appreciate at 4% per year and the rent increases at nearly 8% so it's win win for owners. On the flip side renters continue to spend their money renting and paying the mortgage of their landlords. The 2010 census reported Irvine was nearly 50% rentals [1].. In one of the largest planned communities in the US that is a problem.

[1]https://en.wikipedia.org/wiki/Irvine,_California (see census data for 2010)