Could it be that decision makers are finally starting to take serious mental illness seriously? New Yorkers can be excused for missing the change, inured as they are to the malfeasance and incompetence that have long typified mental-illness policy.

This month, Public Advocate Jumaane Williams exposed the fact that of the hundreds of thousands of ­calls each year to 911 for a mental-health crisis, not one led to dispatch of a mobile mental-health-crisis team.

Our mental-health system ­seems to be hitting rock bottom: Jails are drowning in people with mental illness, streets are littered with the chronically ill and headlines note one preventable tragedy after another.

But even as the failures pile up, signs of hope are appearing all across the country — taking the form of citizens rising up to demand accountability and the prioritization of the most seriously ill.

In New York, Mayor de Blasio’s vast mental-health boondoggle, ThriveNYC, has finally started to give way to a targeted focus on the most seriously ill.

The mayor’s office announced a 30-day intensive review of its use of Kendra’s Law and a $37 million investment to close gaps in services for those with serious mental illness. Plus, mental-health workers will now accompany NYPD officers responding to mental-illness crises. The senseless killings in Chinatown appear to have spurred a realization that spending precious mental-health dollars on frivolous projects while mental-health 911 calls nearly double is politically untenable.

Meanwhile, in liberal San Francisco, an unprecedented homelessness crisis has given Mayor London Breed the opportunity to prioritize care for those most in need.

Despite a vocal constituency urging her to throw good money after bad, her response has been a coherent, serious attempt to address the urgent needs of San Francisco’s sickest. Among other solutions, her UrgentCareSF plan calls for 1,000 new beds in the city’s treatment system and enhancing use of Laura’s Law (California’s version of Kendra’s Law).

Even the federal government appears to have seen the light. In 2015, a series of congressional hearings spurred by the Sandy Hook tragedy exposed an embarrassing lack of focus on serious mental illness among federal agencies.

Their findings noted that a 117-page strategic plan for the US Substance Abuse and Mental Health Services Administration failed to even mention the words “schizophrenia” or “bipolar disorder.” In retrospect, that shouldn’t have been surprising, given the agency didn’t count a single psychiatrist among its more than 600 employees.

Today, the agency is headed by Dr. Elinore McCance-Katz, a well-respected addiction psychiatrist. Under her leadership, the federal government has implemented a multimillion dollar national Kendra’s Law grant program and repeatedly urged states to revisit treatment criteria to ensure the most seriously ill get care before they become dangerous to themselves or someone else.

The Trump administration has even taken steps to catalyze the creation of desperately needed treatment beds by amending longstanding federal Medicaid laws to reimburse costs for inpatient stays.

All of that is not to say that the war is over. It is inevitable that policy makers will forget some of these lessons and backslide on tough ­decisions, wasting the momentum built by the current crisis. Advocates will need to be vigilant to guard against this.

Mayor Bill de Blasio is already under fire for failing to fully incorporate Williams’ recommendations. City Hall has become quiet on a further expansion of Kendra’s Law, even though its success in reaching the most seriously ill has made it a national model.

Have policy makers truly begun to take serious mental illness seriously? It is impossible to say at this early stage. But we have seen that if they do not, we all suffer.

John Snook is the executive director of the Treatment Advocacy Center, a nonprofit that works to eliminate barriers to treatment for people with severe mental illness.