(FORTUNE Magazine) – Shouldn't there have been a shake-out by now?

The torrent of ink spilled about airline ineptitude has been flowing for three years. Everyone agrees the status quo is unsustainable, yet the status quo stubbornly remains. There were six "legacy" carriers on 9/11; there are six today. And the headlines are verging on the absurd. Bankrupt United Airlines has had its federal loan-guarantee applications denied not once but three times. And now it wants the government to bail out its underwater pension plan! US Airways is so schizophrenic that it is at once bandying about doomsday scenarios and announcing a new mini-hub in Fort Lauderdale. Together the six big legacy airlines have totaled $23.3 billion in losses over the past three years and will spill buckets more red ink at $40-plus per barrel of oil. If US Airways goes bankrupt for the second time in three years and Delta follows suit, 42% of the industry's capacity will be operating under Chapter 11 by next spring, according to J.P. Morgan airline analyst Jamie Baker. Morten Beyer, an Arlington, Va., consultant, got so frustrated with this stasis that he recently issued a press release positing that United be merged into American. Sheer insanity? Maybe, he concedes, but "I was just trying to start some constructive thinking."

That's a commodity in short supply. But the endgame may finally be underway, and this fall, market forces may begin to sort out what carriers and creditors have been unable to. Why now? During the peak summer travel season, the legacies' full planes have enabled them to moderate losses or even, in some cases, report small profits. But as load factors cyclically dip below 80% and losses widen, there will be a breaking point. The choice will be simple for the most imperiled majors, United and US Airways: more labor concessions or liquidation. Then, after all this inaction, will come very intense action. If the bankrupt airlines do get concessions and pension breaks, the healthier ones--like Northwest and Continental--must rapidly follow suit or abruptly find themselves at a competitive disadvantage. And American Airlines, which averted Chapter 11 last year with big wage cuts, will have to go back to its unions for more concessions to keep pace with the falling industry pay scales. "What happens at one airline will determine what the rest will be forced to do," says Vaughn Cordle, both a Washington-based industry analyst and a United pilot.

If the market has its way, at least one and possibly two majors won't make it through the winter (right now US Airways is the most likely to be grounded). The one thing that could forestall the winnowing process is Washington. House Speaker Dennis Hastert stoutly backed home-state United's $1.6 billion loan-guarantee bid in June. That failed, but the Illinois Congressman won't let the Illinois airline fail without a fight. Neither will Senate Finance Committee chairman Charles Grassley, who championed a piece of sweetheart legislation allowing airline and steel companies to partially defer scheduled pension contributions in 2004 and 2005. The bill was signed into law in April--just one more symptom of a syndrome bemoaned by Teal Group consultant Richard Aboulafia: "Every incentive is to keep feeding the dinosaur."

Especially when it comes to pensions. If United, which skipped a $72 million pension-fund contribution in July, terminates its four pension plans (as it's said to be likely to do), that $6.4 billion of liabilities would be transferred to the Pension Benefit Guaranty Corp. (PBGC), the federal insurer of defined-benefit plans. That would be an uncharacteristically favorable financial deal for United, which has paid just $50 million in premiums to the PBGC over the past 30 years. If a federal bankruptcy judge approves that move, a stampede of other legacies to bankruptcy courts will ensue. President Bush will be powerfully tempted to mount a rescue operation if, in the months and weeks before election day, airline pensions and tens of thousands of airline jobs are hanging in the balance. "You're not going to watch a major airline go out of business during a presidential election," says consultant Michael Allen of BACK Aviation Solutions. No chance the government will actually get back in the business of airline regulation per se, but Bush could give airlines a temporary pass from pension-plan funding, or help drive down oil prices by tapping the U.S. strategic petroleum reserve, as the airlines have recently requested.

If there's one bright spot in this ongoing fiasco, it's that those legacy airlines that can keep the Grim Reaper from boarding over the next six months could find themselves in a better position than they've been in for years. The post-9/11 slump has forced huge wage concessions from unions, and the majors have reduced their cost disadvantage vs. discounters from 42% to 33% over the past year, according to J.P. Morgan's Baker, who sees that gap narrowing to 25% next year. That's still a hefty margin of difference. But for these dinosaurs, it may be the best news they've had all year.