There are still hundreds of thousands, if not millions, of people who still live and die by large format film cameras for all their photography. There are still millions of people who live and die by rangefinder film cameras (and even digital, for those who can afford it), or instant film cameras. I think its incredibly rare that any technology, of any kind, really ever actually dies and goes away. The only thing that really ever happens is continuing diversification of markets. The advent of HD DSLR still+video cameras is just a new kind of option. Mirrorless cameras are just a new kind of option, that will ultimately service a subset of the current DSLR crowd that uses but hates large, bulky cameras. The advent of the C300 is just a new entrant into an existing market, albeit with differences and improvements that make it unique.
Nothing will ever really "go away" or "die" or "disappear"...things will simply continue to diversify. More options, giving consumers more freedom to pick a tool that better fits their needs and/or wants than they had before. There will always be a (probably very large) holdout group of consumers who prefer DSLR style cameras. There is something to be said for the ergonomics and physical size of a 7D or a D3x over a tiny Nikon 1 body.