Some of the early innovators have indeed fallen along the way. Pentax at one time was the biggest, Minolta was up there too. Some were rolled into different companies, or have become more industrial in nature.
Rollei was big, Mamiya was big, the story seems to be missing the big view and leaves a non photographer thinking that the companies he listed invented the camera.
But Early on, Consumer Cameras were mostly Kodak while PJ's used Graflex. Leica was sought after, but WWII pretty well put them out of favor for many I've had other film and glass plate/sheet film Cameras from the 1800's and early 1900,s as well.
