DETROIT -- Luxury carmakers should all be smiling -- the resurgent U.S. market, and China's booming wealth sector, and other rising large economies, are delivering strong sales and profits to the likes of BMW (IW 1000/36), Mercedes Benz, and Bentley.

But not venerable American brands, Ford's Lincoln (IW 500/6) and General Motors' Cadillac (IW 500/4).

It's been decades now since the two U.S. models set standards for excellence and comfort, ferrying kings, presidents and Hollywood stars -- and both know it.

The market for luxury cars has soared around the world, with the Germans breaking new sales records despite the recession-shrunken European market. Double digit sales growth in China underpinned that.

Yet Lincoln and Cadillac struggle to keep sales from falling: neither has the respect and desirability they need among under-50 buyers in many markets, including the United States, where BMW and Audi are chopping into the demand of the moneyed younger generation.

Last year, Mercedes sold 295,000 cars in the U.S., BMW 281,000, and Audi 139,000, all up one to 2%.

Meanwhile Cadillac sales fell 2% to 150,000 units and Lincoln lost 4% to 82,000.

Both brands suffered deeply in the U.S. financial crisis, when their parents General Motors and Ford fought just to allow their core business to survive.

That set the luxury lines back several years against competitors, at a time when the markets in large rising economies like China and Brazil started to take off.

But their revivals remain stifled: despite showing great technology and power in their vehicles, hand stitched leather seats and the other signs of opulence, in markets around the world they are also-rans.