A new watchdog report points to a peril Mayor Zohran Mamdani refuses to see: New York City can’t actually afford to bleed its golden geese even more just to fund his spending dreams.

Competitive NYC from the Citizens Budget Committee points out that people who moved out of the city from 2019 to 2023 earned $68 billion more than those who moved in — and the exodus is growing: Last year, it spread across all income levels.

Sure, the mayor ran on making Gotham more affordable for most people — but he’s done next to nothing to actually deliver: “Universal” free day care is far off for most; even his rent freeze wouldn’t reduce anyone’s costs.

The CBC report urges Mamdani to make New York City “more magnetic” — more attractive or more valuable to businesses, innovators, job-creators, residents and families.

That includes facing facts about the city’s public schools, which increasingly don’t work for average New Yorkers.

Enrollment in city Department of Education schools plummeted 88,300 between the 2014-’15 and 2020-’21 school years, then dipped another 69,600 by 2024-’25. 

Ever more school buildings are emptying out: 249 schools now operate under 50% of capacity; another 596 schools, at 50% to 80%.

Yet the DOE spends ever more money without delivering better results, and the state class-size mandate will only impose more costs as it forces the hiring of warm-body “teachers.”

Amid his drive to “tax the rich,” Mamdani should realize that if New York state’s share of US millionaires remained at 2010’s level, the city would’ve reaped $2 billion more in personal income tax revenue this year. 

City Hall should be competing with other states to attract, retain and grow millionaires, not singling them out for contempt.

Albany won’t be offering the mayor much more help that the few billion already on the table to fund his hoped-for $127 billion city budget; he’s going to have to find spending cuts to balance the books, let alone fund any new initiatives.

And he should be looking for even more savings to reduce taxes on businesses and job-creators: If he doesn’t start growing the tax base, his choices in the years ahead will be even more grim.