Lower slung than sedans, with long hoods and short decks, they are more aggressively styled and often have higher-output engines.

Adding to the romance, they carry evocative names like Mustang and Camaro, Corvette and Viper, Boxster and Cayman.

They are also increasingly ignored by customers.

JD Power reports that market share for the segment dropped from 4.3% in 2005 to 3.2% in 2009.

Price was no equalizer. Sales of sub-premium sporty cars went from 516,177 to 242,521.

And sales of premium models — Mercedes, Jaguars, and the like — suffered slightly more, falling from 219,732 to 89,429.

Reasons for the drop are clear. Four-door sedans have gotten sporty too.  They perform better, and buyers see no need to trade off the convenience of the extra two doors for a small increase in agility.

Newly-popular coupe styling with fast-sloping roof lines mean sedans don’t have to look frumpy any more.

And as additional equipment has boosted the cost of new cars, young male buyers, who represent the largest pool of interested customers, have been priced out of the sporty coupe market.

Because of their expressive styling — and likely because they often represent an impulsive purchase — sporty coupes sometimes are priced higher than the sedans on which they are based.

Manufacturers justify the higher price by pointing to exclusive body panels, but they overlook the cost they save by eliminating two doors and their associated hardware.

But because of their high style, the appeal of sporty coupes tends to deteriorate after they have been on the market for a year or so.  The phenomenon is known as “design decay.”  So they need constant refreshing to keep from gathering dust on dealer lots.

So why do sporty coupes survive?

Here’s one theory, espoused by George Peterson, head of AutoPacific, a marketing consulting firm: “There is still a small but determined group of enthusiasts who want coupes with manual transmissions.  They probably also want wind-up windows.  Those are the vocal folks product development management responds to.”

Car company marketers and dealers aren’t blameless either.   These are ego cars for companies that can provide a halo for a brand and attract shoppers to a showroom.

Several brands, including Toyota and Acura, have gotten out of the sporty  coupe business.  But others soldier on.

They like the glow the coupes provide for the rest of their line. In my next column, I will road test an entrant from one of the most prolific manufacturers.