Why did production of Trabant and Wartburg cars end after German unification?

Following German unification, the production of Trabant and Wartburg cars ceased primarily because these vehicles were considered environmentally unfriendly and were unable to compete in the free market.1

The integration of the East German economy into the broader German market revealed that much of the region's industry, including its automobile manufacturing, suffered from technological backwardness and low productivity. As consumers in the east gained access to the market, they showed a strong preference for the technically superior and better-presented consumer goods produced in western Germany or abroad over the generally drab products of East German industry. Consequently, major western manufacturers like Volkswagen, Opel, and Daimler-Benz moved to establish operations in the east, replacing the outdated local production models.21