General Motors Corp. celebrated its centennial this year, but after a few harried weeks in November of intensive numbers crunching, accelerated cost cutting and pleading with Congress for help, the auto maker still faces the very real possibility it will not see its 101st birthday.

The irony is cruel for a company that has stood as a pillar of the American economy since before the Great Depression, but whose largesse and lumbering ways threaten to topple the world’s largest auto maker.

Crueler yet, GM Chairman and CEO Rick Wagoner and his management team – under severe pressure by investors to right the company once and for all – must continue downsizing to survive.

“They have to streamline that company in a successful way on a number of fronts, and it starts with the elimination of certain brands and the merging of certain brands,” says John Trentacosta, a partner in the law firm Foley Lardner LLP and co-chair of its automotive industry team.

Wagoner has stubbornly resisted calls for fewer brands and considers founder Alfred Sloan’s “A car for every purse and purpose” strategy an advantage unique to GM.

Paying off dealers carrying eliminated product lines could prove prohibitively expensive. Killing Oldsmobile earlier this decade cost GM an estimated $3 billion, and it’s unlikely the auto maker could stop with one brand, as many analysts suggest a 2-division strategy with Chevrolet and Cadillac might work best.

Trentacosta points to the auto maker’s lineup of midsize SUVs – the Chevy TrailBlazer, GMC Envoy, and Saab 9-7X, which in several weeks will follow the Buick Rainier into extinction with the closing of their Moraine, OH, assembly plant as part of restructuring announced in June.

But he sees the same outdated strategy of slight design and pricing differentiation on identical platforms now playing out with the auto maker’s midsize cross/utility vehicles – the GMC Acadia, Buick Enclave, Saturn Outlook and Chevy Traverse.

“Slightly different but the same,” Trentacosta says, suggesting too many vehicles in the same vein dilutes potential sales. “They need to focus on the core products that give them the best chance to succeed.

“They really need to take three steps back to take five steps forward, but they don’t have the time,” he adds. “That’s the box they’re trapped in. They don’t have the money today to make the strategic changes that will benefit them down the road.”

GM canceled a scheduled interview for this story and declined additional requests, citing the unfavorable timing of lobbying efforts by Detroit Three CEOs in Washington.

Erich Merkle, an auto analyst at Crowe Horwath LLP, says Wagoner understands additional cost cuts are necessary. “He’s a smart man, but he’s somewhat powerless to make the changes necessary to make the company viable,” Merkle says.

He and others argue GM must eliminate health-care benefits for its hourly retirees, an almost unthinkable giveback in the eyes of the United Auto Workers union. The union will take over management of a health-care trust in 2010, according to the landmark labor agreement reached last year, but GM must provide billions of dollars to seed the investment fund.

The auto maker drastically scaled back health-care benefits for salaried retirees in October and stopped matching contributions to 401(k) accounts for active salaried employees.

Over-capacity also will remain an issue. Brand consolidation would do much to more closely align the auto maker with what is expected in 2009 to be another market of light-vehicle sales below 14 million units. But GM did a lot of the heavy lifting in 2008 to position itself for what many analysts consider a sales upturn in 2010.

By May 2009, GM will have shuttered three truck plants in North America, as well as one minivan facility, and lopped off one line of medium-duty truck production. According to Ward’s data, the cuts will bring GM’s capacity down about 8% to 4.5 million units, from 4.9 million units this year.

“If they can get through 2009, they should be all right” with regard to capacity utilization, says Haig Stoddard, an analyst at IHS Global Insight.

GM also added a week of downtime in January at four passenger-car plants and the Delta Twp., MI, facility that assembles the Enclave, Acadia and Outlook. The move comes on top of additional downtime the auto maker scheduled for 2009 in North America earlier this year.

GM will further adjust capacity and production next year by delaying some vehicle introductions, part of a larger plan to cut capital spending by $2.5 billion in 2009.

Additionally, the auto maker will defer some product programs, such as the Cadillac CTS coupe, from three to 12 months. But key programs, such as the Chevy Volt extended-range electric vehicle and the fuel-sipping Chevy Cruze compact car, remain intact, says GM Vice Chairman Bob Lutz.

“We also protected and even increased global spending on fuel-economy improvements,” Lutz says in an email to Ward’s. In fact, Lutz thinks the new product cadence will provide a better launch schedule over the next two years, as GM pushes 15 new vehicles to market by the end of 2010. He says 14 of the models will be fuel-efficient cars or CUVs.

“It’s also important to point out that even though we have some product delays, they are just that – delays. And some are short ones at that,” Lutz says. “Many of our product programs have not been impacted at all.”

Clearly, GM intends to stick with its thinking that, despite record-low gasoline prices, consumers have made a long-term shift away from gas-guzzling trucks to more economical passenger cars and CUVs.

“The recent drop in fuel prices is directly related to a drop in demand caused by the severe economic slowdown, both here and around the world,” Lutz says, noting consumers use oil for much more than just cars. “We think that demand will be back, and so prices will return to higher levels as the economies of the world begin to recover and oil supplies become tighter again.”

Lutz suggests Americans need the incentive of high gasoline prices to pull their fleet closer to the European model, supported by heavy taxes, to meet strict new corporate average fuel economy rules.

“The worst-case scenario is for fuel prices to remain low, because that means customer demand will remain high for larger vehicles,” he says. “Very few people will want to change what has been their ‘nationality-given’ right to drive big and bigger if the price of gas is $1.50 or $2.00 or even $2.50.

“Those prices will put the CAFE-mandated manufacturers at war with their customers – and no one will win in that battle,” Lutz continues. “Instead, in tandem with the efforts of manufacturers, we need consumers to be part of this transformation – with government incentives to buy more fuel-efficient vehicles and adopt new technology like the Volt.”

But with the ongoing credit crisis, few people can buy anything right now, big or small, Lutz admits.

“Until the issue of credit availability is solved in this economy, and consumer confidence dramatically rebounds, all sales – including those in the auto sector – will suffer,” he says, declining to place any blame with GMAC LLC.

The auto maker’s captive lending arm decided in October to stop financing consumers lacking top credit scores.

The decision led to some speculation of a frosty relationship between GM and GMAC’s majority owner, Cerberus Capital management LP. Cerberus also owns 80% of Chrysler LLC, which GM had sought to absorb in recent months but called off talks to focus on its own liquidity issues.

In a month when sales plunged 47%, GMAC wrote fewer than 10% of GM’s loans in October. Typically, a captive unit finances up to 80% of an auto maker’s sales.

“We need them, and they need us,” Lutz says of GMAC. “They got hit with the same (financial market) tsunami we did. They have responsibilities to their shareholders and investors just like we do. We’re working with Cerberus and GMAC to get through this thing.”

Getting through would appear to mean garnering federal bridge loans to help GM restructure further next year and push toward 2010, when consumer demand is expected to pick up.

But even that, says GM Chief Operating Officer Fritz Henderson during a conference call to discuss GM’s bleak third-quarter financial report, is no guarantee.

“We’re not counting on 2010 as a panacea,” he tells journalists and Wall Street analysts. “We are not writing it off, either.

“We have to…try to plan our business around a more conservative, frankly a more difficult environment,” Henderson says. “And if we are able to do that, and that’s where we’re spending 100% of our time, then we’re going to have a favorable surprise if the market’s better.”