Homeowners are a reliable voting bloc. Rezoning single homes would make housing more affordable while adding to the city's vibrancy. It would also reduce existing home values.
I'm not an american so I probably don't get the real estate market in the US. But wouldn't rezoning actually increase the value ? Not of the home itself but of the land on which it is built.
If your $1M home can be turned into a 10-flat building at $300K each, wouldn't real-estate developers buy your home (even at a premium) to destroy it and rebuild on it ?
Let this happen ten times and you have 100 new units on the market. Since nobody moves to a city to live in a particular building (i.e. housing demand, locally, is relatively independent of housing supply, at least in the short run) this will drive the apartments' prices down. That, in turn, will exert downward pressure on the price of the single-family homes.
A years long process won’t do anything to help thousands of homeless now.
2. Rents increase.
3. More people become homeless.
http://q13fox.com/2017/11/06/study-says-rising-rents-tied-to...
What do you think the underlying cause of homelessness in Seattle is?