There's a country song that was popular a few years ago named, "There Ain't No Future in the Past."
Like a lot of manufacturers that have fallen from a perch atop an industry that they seemed destined to dominate forever, the post-WWII German camera industry forgot that what the market demanded in the past does not necessarily indicate what the market will want in the future. Like Kodak, for too long they concentrated on protecting the turf they had already won which was increasingly becoming irrelevant instead of predicting changes in the demands of the marketplace and defining the future of photography.
The same thing happened to American automobile makers centered around Detroit, Michigan in the 1970s and '80s. It happened to American television makers who were supplanted by the Japanese. The Japanese television makers then let themselves become upended by the Chinese and Koreans.