The election of Zohran Mamdani as New York City mayor set off — for his fan base, anyway — great expectations of a more “affordable” city. But the Democratic Socialist hasn’t even been sworn in, and some of his marquee promises are already history.

Start with free buses. For a city dependent on public transportation, free buses are a nice idea but also a bad idea. Fares pay for the buses, and even if you plug that hole with another revenue source, free buses would siphon riders from the subways, in effect defunding them.

Mamdani spun visions of the state raising taxes to cover the $700 million in lost fares or find the dough elsewhere. New York Gov. Kathy Hochul says she’s not interested in either notion. The governor’s support is essential: The Metropolitan Transportation Authority, which runs most of the region’s mass transit, is a state agency. Barring the unforeseen, the free bus idea has left the terminal.

Affordable housing? All opposed raise your hands. Now define it in a New York (or San Francisco) context.

The cost of living in New York City has always been high. It’s high because the demand is intense and the supply is limited for obvious reasons. It’s not Dallas or Omaha with prairies to sprawl into. It’s densely built and mostly hemmed in by bodies of water.

At some point, people who want cheaper housing or more space need to move to places that actually offer it. Generations of New Yorkers have done that, with many moving back when their kids are grown.

Even within the New York metropolitan region, there are lower living costs than in the choice parts of Manhattan or brownstone Brooklyn. But the Gen-Z professionals who power Mamdani demand the hot urban scenes while also fuming at the $20 their hip hangout charges for a martini. They should be mindful that Mamdani has yet to propose government-run cocktail lounges. Also, there’s no law against mixing drinks at home.

It’s not true that the rents only go up. They have historically dropped during crises: after the 9/11 terror attack, during the 2008 financial meltdown and very much in the COVID pandemic’s grip.

Mamdani could create crises reducing demand for New York City. His attacks on the New York Police Department have created fear of a crime wave. And his vows to raise taxes on already highly taxed rich residents could cause an exodus of businesses and with them, jobs from the city.

That said, building more residential units where construction makes sense would be helpful. But bulldozing cherished neighborhoods for apartment blocks is sure to clash with quality-of-life concerns.

Thus, one of Mamdani’s proposals crashed faster than the Hindenburg. He wanted to build “affordable elderly housing” on a community garden in the Nolita neighborhood. The Elizabeth Street Garden is an acre of greenery, oddly placed statuary and whimsical paths offering pastoral escape from the hardscaped streets of lower Manhattan.