For a while, fuel cells and battery electrics had more or less balanced pro/con sheets. Both technologies were costly in their infancy, with little in the way of supporting infrastructure. Batteries could be charged at home, but slowly, and limited range meant long drives were out of the question. Hydrogen fueling is relatively quick, and fuel-cell vehicles currently have the advantage in driving range. In recent years, though, EV charging infrastructure has expanded rapidly, and batteries have become increasingly more affordable and energy-dense. Fuel-cell development just hasn't matched the pace of battery electrics.
Daimler is just one company for whom the pendulum is swinging away from fuel cells. Toyota, which has put a lot of effort into the introduction of the Mirai, has plans to develop electric cars. Hyundai, which sells the Tucson Fuel Cell and recently previewed its next-gen hydrogen car, has also apparently seen the light of EVs (and its Ioniq trio is a promising sign for its grasp of electrification). Battery stalwarts like Nissan and Tesla may be closer to vindication.
Hydrogen still has some momentum, even in Germany, with an expanding fueling network and even a fuel-cell carsharing program. Mercedes plans to launch a fuel-cell plug-in hybrid version of its GLC crossover, and we can expect automakers to keep hydrogen tech development in place. Even if it doesn't reach mass appeal, it could still thrive in certain markets (perhaps Japan and Korea) and applications (commercial, military). And whenever an automaker – Daimler included – does release a new hydrogen car or announces a milestone in fuel-cell development, we still can expect to hear a rosy vision for H2. At least for now, though, it appears that the battery EV is the popular horse to back.