Democrats Must Fix the Housing Emergency (nymag.com)
Meanwhile, Real Estate was the top funding sector for Democrats in 2018 (for Rs it's #2). A big part of these investments are REITs (Real Estate funding Trusts), which buy up rental properties in order to pay profits distributed to investors. More housing would negatively effect the value of these resources, so they won't help build any. It might be possible to make money building and operating new housing, but that involves work and hazard. It's much easier just to make money on existing housing that will keep going up in value because of increased demand.
Top Sectors – 2018 – Personal FinancesPersonal Finances • OpenSecrets
A bit lower down the ladder (but still in an enviable position), we have the Democratic faithful like the boomer profiled in this piece:
California’s Housing Crisis and the Fight Over 20 Townhomes – The New York Times (nytimes.com)
This is the widespread attitude of the backbone of the party, the upper-middle class property owners (in both city & suburb) who provide the money, volunteers, and organization for the party. It's not just Nimbyism, they're are basically against more housing anywhere. If less kids sleeping on the street means lower property values for them, they'll have none of it.
State & Local governments control most matters related to real estate and construction. If Democrats didn't want things to be the way they are in the cities and states they control, they have the power to mitigate this problem significantly. The fact that they haven't speaks volumes.
Even looked at through the most neoliberal lens, this is total bullshit. The industry could supply more housing, but the already well-off are making damn sure it doesn't happen so they can gain more wealth without any work. If this isn't justification for almost any form of resistance, I'm not sure what is.
Edit, since I'm being accused of being a Republican Simp:
Also, let me put in a disclaimer, I'm not telling you to vote for Republicans; they will screw you in other ways that (probably) will be worse. (Their favorite trick is to cut taxes on the rich, then freak out about the deficit, then cut spending that helps the middle class, helps the poor, pays for necessary infrastructure, could get you out from underneath your health coverage enterprise, might make it easier to get an education without going into horrendous debt, etc.) On this issue, however, the Dems are the main antagonist and the high cost of housing is one of the most effective tools the bosses have to control you.