YIMBYism is based on some simple, basically correct, ideas:
- Many cities are too expensive because not enough housing is being built relative to the demand to live in those cities. This leads to competition for a scarcer and scarcer housing stock and drives up prices. Housing is a good traded in a market and the laws of supply and demand apply.
- If you claim to care about environmental protection you have to care about infill development. While low-density urbanization can be effective in alleviating high housing costs, it gobbles up natural habitat and increases per-capita driving (and hence greenhouse gas emissions). In some cases the extra driving cancels out some or all of the benefits of cheaper housing. Infill doesn't kill habitat and gives people chances to at a minimum, drive shorter distances, and at best walk, bike and use transit. Our cities may need to expand horizontally to deal with the crisis, but they also need to grow vertically.
- Housing subsidies aren't sufficient to solve the problem. America's biggest housing subsidy, the mortgage interest tax deduction, does basically nothing for renters. Subsidies actually targeted at renters like Section 8, or at rental housing like Low Income Housing Tax Credits, while good policy, are a drop in the bucket compared to the demand for affordable housing.
- Infill development requires changes to neighborhood character. Sometimes we like to gloss over or sugar coat this, but it's true. While there are approaches to infill that are designed to be as compatible as possible with neighborhoods of single-family homes and separated land uses (e.g. Missing Middle and backyard granny cottages), if we're really going to solve this problem in cities like Los Angeles, some places are going to have to change in more visible and, to some, uncomfortable ways. The more we grow upwards in the places where it makes the most sense (e.g. existing downtowns, existing commercial land, and the areas within one kilometer of major transit stops) the more of low-density suburbia we can preserve, if that is a goal which is important to a community.
- Land use decision making processes have failed to represent the interests of renters and the most vulnerable people in our society, often because cities use exclusionary zoning to self-select their populations. This necessitates more people getting involved in planning advocacy at the local level, and shifting the locus of land use decision making to levels of government that are sometimes more willing to account for the needs of a diverse constituency, such as regional or state governments.
Check out this list of YIMBY organizations from the 2016 YIMBY Conference in Boulder, Colorado. Also, don't forget that there are some classic groups out there that work at a national scale on these issues such as Congress for the New Urbanism and Smart Growth America. Give them some money if it's not all going to the rent, and get involved. YIMBYs of the world unite!