One thing we know about Mayor Bill de Blasio is that he’s serious about creating affordable, quality housing for all New Yorkers.

“This is literally the largest and most ambitious affordable-housing program initiated by any city in this country in the history of the United States of America,” de Blasio declared when he announced his “five-borough, 10-year plan” in May. “It is the largest, fastest affordable-housing plan ever attempted at a local level,” he added, vowing to “change the face of this city forever.”

Hear that, kids? Your rent worries will soon ease. Great news!

I wonder if the new promise will work out like similar vows from Mayor Michael Bloomberg (“We’ll pursue the most ambitious affordable-housing initiative in New York’s history,” 2006), Mayor Ed Koch (“We won’t rest until the housing we so desperately need is built. The housing shortage is our most severe and intractable problem,” 1986), Mayor John Lindsay (who pledged $2 billion to build “160,000 units of low- and middle-income housing,” 1965) and Mayor John “Red Mike” Hylan (who said the law of supply and demand should be repealed when it came to housing, citing WWI as the emergency of the day — 1920).

A resource New York City has never been short of, quipped Peter Salins of The Manhattan Institute, is housing policy. Ever wonder why there is a perpetual crisis of affordable housing when our elected officials have always promised to take care of it? Why does no one seem to complain about an affordable-automobile crisis or an affordable-food crisis or an affordable-television crisis?

The only things that seem alarmingly expensive are the things government is forever pledging to make more affordable: housing, education and health care.

De Blasio was elected to carry the flag of fairness. But which is fairer: allocating living space in, say, Manhattan the way we allocate everything else (selling to the highest bidder) or allocating it based on the spiderweb of regulations, familial connections and insider ties that prevails today?

Take the 80-20 rule that prevails at most of the fancy new buildings you see shooting up in the best nabes. One-fifth of the apartments are rented far below their value to “moderate-income tenants,” meaning, for instance, some law student from Scarsdale currently getting a monthly check from her dentist daddy. These lucky few winners will simply be subsidized by their neighbors, who are paying a topped-up version of market rate because of the artificial scarcity created by so many apartments being rented for less than they’re worth.

At the new building at 500 W. 30th St., ordinary renters pay about $7,200 for a two-bedroom. The lucky lottery winners in the subsidized apartments, meanwhile, pay . . . $780. The developer (Related Cos.) was happy to comply with the 80-20 policy because it received many millions in various kickbacks, er, tax breaks.

That’s right: You, ordinary New York city taxpayer, are giving severely wealthy real-estate developers like Related boss Stephen Ross (net worth: $4.8 billion) millions in corporate welfare so a handful of lucky bastards can get a 90 percent discount on a luxury apartment.

The mayor can brag about how he’s “increased the supply of affordable housing” by a negligible amount. De Blasio’s “ambitious” goal is 80,000 new affordable housing units in the next 10 years.

That’s 8,000 units a year. In a city of 3.35 million housing units, that’s an increase of 0.2 percent a year. Oh, and we added 61,000 residents last year. Still feel pretty good about your chances of winning the “affordable housing” lottery? Don’t stop believin’!

De Blasio could, of course, increase the supply of affordable housing by lifting archaic restrictions. Williamsburg, Brooklyn, for instance, is still frozen in an Eisenhower era of amazingly ugly vinyl-covered low-rise buildings because of decades of anti-density zoning rules and requirements that developers create a certain number of parking spaces if they want to build. But even that wouldn’t make our most desirable neighborhoods cheap.

Bloomberg was correct in saying New York is a luxury product, and luxury products are not for everyone. If you’d rather live in a discount burg, go live there instead of bewailing the laws of the marketplace. Do you walk into a new Toyota showroom with $499 and expect them to come up with a car for you? There is no constitutional right that everyone who wants to live in New York can.

And yet, surprise! As of 2011, New Yorkers spent, at the median, 32.5 percent of income on housing. This is just about the only statistic you can find where we rate about average: Nationwide that figure is 33.1 percent.

Is the rent too damn high? In fact, it’s pretty much exactly where you’d expect it to be.