The Stanley. The Fox. The Earle. The Erlanger. The Mastbaum.

The roll of Philadelphia's vanished movie palaces goes on and on, like the credits of a blockbuster film. Soon, two more historic names could join the list of the fallen: the Boyd and the Royal.

Preservationists have struggled for more than a decade to save these two great movie houses, among the last survivors of Hollywood's golden age in Philadelphia. They've come close several times to finding uses for the historically landmarked buildings, but time is running out. In separate cases, the owners are pressing the city for permission to demolish the auditoriums, the very heart and soul of the theaters.

Live Nation, which bought Chestnut Street's Boyd Theater in 2006, is on the verge of making a deal that would allow a Florida chain to gut the majestic Art Deco interior and install high-end screening rooms. South Street's Royal Theater, once an important hub of black culture, would get a similar filleting by Kenny Gamble's Universal Cos., which has sat on the building for a dozen years without so much as fixing the broken sidewalk. He wants to use the site for an apartment house.

Right about now you're probably wondering, "Doesn't city landmark status protect these theaters from demolition?"

Theoretically, yes. But in a city that increasingly hitches its future to developers' promises, a historic designation has become just another fungible commodity, to be traded in when the right time comes along.

Both owners have decided to ask the city Historical Commission to void the theaters' historic status on the grounds that redeveloping them in their current form is a "financial hardship." If the commission buys their argument, they would demolish everything behind the main facades. The maneuver, known as a facadectomy, turns three-dimensional buildings into cardboard cutouts. The first hearing for the Boyd is Dec. 17.

We've seen the financial-hardship tactic used a lot lately, and with increasing success. The owners of the Church of the Assumption, on Spring Garden Street, won a demolition permit in 2010 by claiming there was no feasible way to reuse the building where Katharine Drexel, a Roman Catholic saint, was baptized. Last year, the University of Pennsylvania dealt with a problematic mansion at 40th and Pine Streets by successfully making the same argument. Those demolitions are on hold while the courts review the decisions.

You might think that a historically certified building would have to be practically falling down to qualify for hardship, but that's rarely the case. Both the Boyd and the Royal are structurally sound and retain much of their original detail. They are simply old buildings that are challenging and expensive to reuse. Their owners have given up trying.

The temptation to grant financial hardship will be great. Both theaters look like wrecks. The Royal has been closed since 1970, the Boyd since 2002.

In the last few years, Chestnut and South Streets have rebounded with new shops and renovated buildings. So, we will certainly be told that the theaters, covered in rotting plywood, stand out like tumors amid that urban vitality. No doubt the owners will claim that facadectomies are actually a way of preserving history.

Despite all the city's economic woes, it's important for the commission to remember one essential fact: Once the theaters are gone, their architecture and memories are lost forever.

The Boyd is easily the more spectacular of the two, and the more salvageable. Designed in 1928 by the great theater designers Hoffmann & Henon, it was given the full Art Deco treatment, and is the only true Art Deco movie palace that conservative Philadelphia ever built. "When you think about all the luxurious interiors in the city - City Hall, 30th Street Station - none of them have this decadence," said the Preservation Alliance's Ben Leech. "It's something rare."

The narrow Chestnut Street facade, which is all most people know, only hints at the lavishness inside. Hoffman & Henon plastered the walls of the 2,350-seat auditorium in blazing colors and Jazz Age forms. Waves of sculpted plaster surround the screen. The mirrored lobby is as grand as a banquet hall and features a mural celebrating the history of women's achievement, quite an unusual subject for 1928.

Architecturally, the Royal can't compare, though its history resonates deeply. Designated historic in 1978, it was Philadelphia's first black-owned theater when it opened in 1920, and hosted performers like Bessie Smith and Fats Waller. Some interior decoration may still remain, although Gamble's company has done almost no maintenance since acquiring the building in 2000.

The owners of the Florida movie chain, iPic, have been lobbying hard to convince various interest groups that their screening-room concept is a worthy replacement for the Boyd's stunning interiors. They've brought the humble multiplex upmarket by creating an environment resembling a home theater, with leather recliners and table service.

It's an appealing enough way to see a movie, assuming you have $24 to spend on a ticket, but why does it have to be located where the Boyd now stands? When I put that question to iPic CEO Hamid Hashemi, he replied that his company can't afford any other site. Clear Channel is willing to dump the Boyd for $4.5 million, about half of what it paid seven years ago.

In the history of theater rescue stories, seven years is nothing. The cities that have restored their great movie places - and dozens have - devoted decades to the effort. New York is just putting the finishing touches on the Loew's King Theatre in downtown Brooklyn. It had been closed since 1978, but will soon have a new life as a performing arts center. The transformation would never have happened without the help of the borough president, who persuaded the city and state to kick in seed money. The Boyd and the Royal also need government champions and public funds to succeed.

Mayor Nutter was a big supporter of giving the Boyd historic status in 2008. That was just five years ago, but there is an increasing presumption in Philadelphia that the designation comes with a clock. If you can't develop a historic building in a few years, the thinking goes, it's time to tear it down. But a preserved building is supposed to be preserved forever.