Modern-day, four-door sedans have adapted the sportier styling that once was the trademark of coupes, said Sam Fiorani, vice president at AutoForecast Solutions.
"With the added utility of rear doors and a fully usable back seat, sedans have made two-door models redundant," Fiorani said. "Two-door coupes and convertibles now only appeal to a handful of buyers who find the extra openings offensive. These buyers are slowly moving to sedans or utilities, or aging out of personal vehicles altogether."
Coupes and convertibles are a shrinking part of a shrinking segment, in a shrinking overall market, noted Greg Gates, vice president at Swickard Auto Group, which operates three Mercedes-Benz stores.
"There's just not that many customers who are looking for a $150,000 convertible," said Gates, referring to the S-Class convertible. "Are there customers for coupe and cabs from time to time? Sure. But we still have plenty of great products to sell to them and we can find something that's going to fit their needs."
Mercedes is looking to dump other low-volume sporty sedan models, too. The automaker discontinued production of the low-volume SLC roadster in April. U.S. sales of the SLC dropped to 1,840 last year and have fallen steadily since topping 10,000 a year in the early 2000s.
It's unclear which AMG GT model Mercedes plans to cut from its U.S. lineup. Fiorani forecasts that the four-door coupe will be discontinued globally once the product life cycle ends in 2023. The four-door GT and CLS compete for the same buyers in the price range with the S-Class sedan, reducing the profit on all three models.