By 1958 it was the advent of the Japanese cameras that was radically changing the market place. It wasn't particularly any one make although Nikon were spearheading the professional market for photojournalists.
In contrast American and European manufacturers were mostly making lack lustre often clumsy cameras, there were exceptions like Leica and Hasselblad, and some of the more innovative European cameras were being made in East Germany but poor quality control held them back. The Praktina system was the firts full SLR system with a motor drive etc.Later the Prakticamat was the first SLR with TTL metering just beating the Spotmatic into the dealers.
Looking at adverts for the time it's easy to spot the complacency in companies like Kodak who were still selling Box bownies and a motley range of other cheap cameras, in comparison Fuji were offering high end SLRs and Rangefinder cameras.
Perhaps the biggest mistake after WWII was the reliance on leaf shutters in many West German cameras this made SLR design particularly awkward and the arrival of well engineered, well designed, reliable Japanese cameras with their clean ergonic styling which also made them much easier to use just devastated the German market which couldn't repsond quickly to change.