In 2005, 300 furniture wholesalers filled the San Francisco Mart. In 2008, 30 remain. Last week, those were given notice to vacate the 1937 Art Deco building at 1355 Market St. by the end of the year so that the developer can turn it into office and retail space.

The explanation for such a dramatic change? Lights on, Las Vegas. Lights out, San Francisco.

"The wholesale buying pattern is changing in the furniture business," said Roseann Carini, the Mart's general manager from its 2005 heyday to its 2008 mayday. "The showrooms that did their business through biannual buying (two shows a year that attracted merchants from all over the world) relocated to Las Vegas when the World Market Center opened there (in July 2005). We attempted to activate year-round businesses, but we were not successful in attracting new operators."

The Internet, home-decorating television, environmental concerns and the building slump have altered the way consumers shop for and buy furniture, so wholesalers and retailers have adjusted. Efforts by Carini and the Mart's developer, Adco, to revitalize the building focused on attracting Bay Area designers to potentially 11 floors (1 million square feet) of furniture, carpet and accessory showrooms by offering regular promotions, seminars and sample sales.

Two years ago, there was talk of transforming the Mart's upper floors into condos, but that plan proved too cumbersome. Last summer, Adco announced it would market some space for offices and retail stores; with last week's announcement, the building will close and undergo renovations for up to 18 months, Carini said.

"This has not been in the works at all," Carini said. "We will still do what's on the calendar for January, but we won't be having any of the other events we'd planned for 2008."

There surely will be public sample sales staged by the operators who have to move out. The showrooms that remain have been successful enough with their designer clientele that none is using the Mart's demise as an excuse to go out of business; all are shopping for new spaces in the South of Market neighborhood that houses the San Francisco Design Center, Carini said.

They're not exactly shocked by the announcement, and they're not exactly heartbroken.

"We knew we needed to be in a better environment for our product, because we're the high-end guys," said Direct Designs Home owner Karen McMullen, whose collections include John Charles and Dellarobia. "We've been here 25 years, and this is something we've wanted to do for some time. Sometimes you need a little shove.

"Roseann lost 42,000 square feet of showroom in 2007 alone. They tried to make it work, they did everything possible, so there's no animosity anywhere."

Later in the year, several showrooms may unite for a public sample sale. Liquidation sales have already begun at Direct Designs Home and Showroom 500, which just introduced the Metropolitan Home Collection. The Mart building has never been open to the public, but consumers who see something online that they want can call and request an appointment to visit.

"I have signed a letter of intent for a showroom in the (San Francisco) Design Center, but have to sell 10,000 square feet of merchandise in a few weeks," said McMullen, whose Web site, www.directdesignshome.com, catalogs some of the sale items. "I think once designers know we're leaving, business will fall off drastically."

Wanda Spangenberg, whose 36 lines fill the Mart's seventh floor, is more concerned about making the right move than making a fast move. "The timing for me was a shock, but the handwriting was on the wall that this building was going to change its business model at some point," she said. "What owner can support a building with the occupancy rate where it was?"