In New York City, Sept. 11 is something of a somber, unofficial holiday, with quiet memorial events around the city and twin beams of light rising from the Manhattan skyline.

It is not, however, an official federal holiday — which is why businesses and schools don't shut down. Instead, Congress dubbed it a "National Day of Service and Remembrance," which lawmakers officially named "Patriot Day" in 2001.

Congress has the power to make Patriot Day a permanent federal holiday. Right now, there are 10: New Year's Day, President's Day, Independence Day, Thanksgiving Day, Christmas Day, Memorial Day, Veterans Day, Columbus Day, Labor Day, and Martin Luther King Jr.'s birthday. Only federal employees and employees in the District of Columbia are guaranteed these holidays off, which is why you might still have to work on Columbus Day. (People in the Washington D.C. area also get to enjoy Inauguration Day once every four years).

Shortly after the 9/11 attacks and during their 10th anniversary, there were plenty of calls to make Patriot Day a holiday, mostly out of a fear that it would be forgotten by an apathetic public. Joe Brettell, a Republican consultant living in Virginia, made that case on Fox News:

In the years following the 9/11 attack, Congress has taken care to mark the day with moments of silence and resolutions. But those proclamations, while important, rarely gain the awareness of everyday Americans … Surely this effort will inspire the cynics to suggest that commemorating September 11 will eventually relegate it to another day of barbecues and baseball games, with only passing regard given to the heroes of that day. Yet in a deeper sense there can be no greater response to an attack that was launched at our very way of life than to celebrate the institutions, gatherings, and freedoms that drove our enemies to violence. [Fox News]

There is some credence to concerns that a 9/11 holiday would be trivialized by commercialism. Yesterday, Tumbledown Trails Golf Course, located near Madison, Wis., got in trouble for offering nine holes of golf for $9.11 to "commemorate" the 12th anniversary of 9/11.

September 11 is also just a few days after Labor Day, meaning the United States would either have to move Labor Day to some other date or deal with two short work weeks in a row.

That gets to the biggest reason Sept. 11 probably won't be a holiday anytime soon: Federal holidays cost money. A lot of money. According to Rasmussen, every holiday costs the federal government $450 million in employee pay and lost productivity.

States have also been reticent to give their employees an extra holiday. In 2002, the New York state legislature decided not to make 9/11 a holiday after the state comptroller said it would cost $43 million. Other states, like Colorado, have also briefly considered it before scrapping the idea because of costs.

In 2007, Montana state Sen. Don Ryan tried to solve the cost problem by suggesting that 9/11 be made into a holiday instead of Columbus Day. One Italian-American lawmaker, according to the Los Angeles Times, told the Irish-American Ryan, "Why don't you take away St. Patrick's Day?"

And that was before the financial crisis hit in 2008. In that light, it's easy to see why many politicians prefer a somber day of remembrance that doesn't offend anyone or strain state and federal coffers.

Just because it's not a federal holiday now, however, doesn't mean it never will be. Martin Luther King Jr.'s birthday wasn't made a holiday until 1984. Memorial Day, initially created to honor fallen Union soldiers, wasn't declared a federal holiday until 1967. And Thanksgiving? That was officially made a federal holiday by President Abraham Lincoln, more than two centuries after the Pilgrims landed at Plymouth Rock.