It is possible for a new player (Sony) dominate the market for cameras in six years. But lenses, flash, and accessories require more time to become solid. The wealthy amateurs can change your camera every year, while the professionals choose thinking about the reliability of camera equipment over time.
However, Sigma and Zeiss could be a wildcard for Sony if she does cameras that satisfy the desires of photographers.
Sony merely put their name on Minolta, so they are not new to photography.
Samsung is a company to watch out for, they have the dollars, and when they put their mind to it, they can produce.
Still, I'd bet on a Chinese company emerging, or a offshoot of a existing one. Some of them are ruthless, and have no qualms about playing dirty tricks to steamroller the competition. One comes to mind, but Ill not name them.