Finally, some folks are having an existential crisis about a housing shortage that could send the state into a socioeconomic death spiral.

The Southern California Association of Governments, a planning agency for six counties that contain nearly half of the state’s population, staged a California Housing Summit on Tuesday in Los Angeles to call attention to the shortage and explore ways it could be addressed.

A lengthy report presented to the session laid out arithmetic of the crisis — a shortage of at least 600,000 units in SCAG counties (more than a million statewide) that grows as construction lags behind very modest population growth, and soaring costs that far outstrip stagnant incomes of middle-class and poor families.

Increasing shortages and ever-rising costs discourage job-creating investment, driving it to other states with much lower housing burdens, and contribute to a net outflow of Californians in search of jobs and housing they can afford.

“The housing crisis in California is due to a combination of both a housing shortage and a lack of affordability,” conference attendees were told. “The problem is not limited to housing for low-income families. The goal of the housing summit … is to get decision-makers to say ‘yes’ and build housing with actionable options.”

NIMBYism lies at the core of the crisis — the reluctance of those already housed to accept additional development, particularly high-density and low-income units, in their neighborhoods, fearing adverse impacts such as crime or traffic congestion.

Local governments, especially cities, in turn are reluctant to override resistance from their constituents, compounded by misguided environmentalism and pressure from unions for labor contracts.

The anti-housing mindset is most pronounced in coastal regions, such as Los Angeles and the San Francisco Bay Area, where shortages and cost increases are most pronounced.

In the SCAG region, according to the report, the median housing rental price has increased more than 20 percent in the last 20 years, adjusted for inflation, while its median income has dropped by 5 percent. Poor urban families routinely devote two-thirds of their incomes to keeping roofs over their heads.

The report suggests — and conference panels discussed — a variety of strategies for overcoming local resistance and generating more financing for low- and moderate-income housing.

In a sense, Tuesday’s event didn’t tell us anything we didn’t know already.

Political figures from Gov. Jerry Brown downward have been talking about the housing shortage for years. But so far, they’ve been unwilling to take the controversial steps needed to alleviate it — not even Brown’s baby step plan to bypass local hurdles for some projects.

It ran into opposition from local officials unwilling to have their land-use powers abridged, from unions and from environmental groups.

It will take a great deal of political courage to do what’s needed to be done. But failure will hasten California’s evolution into a state of rich and poor, with an ever-shrinking middle class.