NEW YORK (Fortune) -- We can only hope that Ford isn't deterred from selling Jaguar by the report that Hyundai isn't buying.

Detroit's problems with quality and with making profitable small cars are well-documented. But nobody has satisfactorily explained why Ford (Charts), General Motors (Charts) or Chrysler (Charts) have not been able to develop a luxury brand to compete with the Germans, or even the Japanese.

Ford has sunk $10 billion or more into Jaguar since it bought the British car maker in 1989, and today it's back where it started - rethinking Jaguar's entire business model.

General Motors is little better off with Saab, which it acquired in pieces beginning about 15 years ago. It hasn't made a nickel either, and is currently integrating it piece by Swedish piece into its German Opel operation.

For its part, Chrysler dabbled with Maserati and Lamborghini in the 1980s and 1990s but has stayed out of the upscale car game since then.

Despite Detroit's efforts, foreign manufacturers remain the kings of the upscale car business. Mercedes-Benz is the oldest car company on the planet and has seldom wavered from its determination to build the best cars available - regardless of price.

Newcomer BMW, which didn't get seriously started in the car business until after World War II, has thrived by making its name synonymous with sporty luxury. Toyota (Charts) started Lexus from scratch in 1989 and made it a winner with superlative engineering, unimpeachable quality and a nonpareil dealer network.

Among the up-and-comers, Audi is a perennial aspirant to the top tier that never quite makes it over the hump. Infiniti has impressed with a blizzard of new models but still lacks a certain cachet. And Cadillac has scored big with its entry level sedans and SUVs but still comes up short in the $60,000-and-above price category.

Automakers covet an upper-tier ranking because profits in the luxury range are lush, customers are exceedingly loyal, and a high-line brand can cast a rosy glow over more mundane popular-priced cars. So why have Ford and GM flopped so badly?

In Ford's case, Jaguar has suffered because of a lack of understanding about what the brand stood for. Ford successfully fixed Jaguar's notorious quality problems - the cars are now among the most dependable in the world - but forgot to maintain the brand's charisma.

Designers reached uncertainly backward for cues from Jaguar's past but failed to imbue them with any new sense of dash and grace. The perigee came when Ford decided to rework the mundane Ford Mondeo into the X-type Jaguar without asking what connection a small, underpowered sedan had with Jaguar's heritage of racing thoroughbreds.

Whoever winds up as Jaguar's owner is likely to strike the X-type from the model lineup and forget that it ever existed.

GM faced a different set of problems with Saab but was equally unable to come to grips with them. It got taken in by the romantic idea of dedicated Swedish engineers working in splendid isolation from the rest of the auto industry, without considering the economics of developing two unique Saab car platforms with tiny sales volume.

Despite high costs and shoddy quality, Saab was allowed to go its own way for years before GM smartened up and integrated it into the rest of its auto operations. Saab is on sounder footing now - but is a Saab still a Saab if it isn't engineered or manufactured in Sweden.

With all that as background, should Ford be looking for a buyer for Jaguar? Absolutely. If nearly two decades of mismanagement isn't enough evidence, Jaguar, in its new incarnation will be selling around 100,000 cars a year. That's barely a pimple on Ford's global business of 6.5 million cars a year. As a volume manufacturer, Ford should be thinking big and not concerning itself with the niche marketing of a brand like Jaguar.

If Jaguar alone is not appealing to a potential buyer, Ford should throw Land Rover and Aston Martin into the deal as well - a trifecta of British luxury brands. I could see France's Renault or Peugeot-Citroen stepping up to take them over, or perhaps some adventurous private equity investor.

Anyway, it is past time for Ford to say "Cheerio" to its English patient.