Sony's staying, as they're a major sensor OEM, which is why they have to cripple their own cameras along the way. The Tower Jazz poobah said something along these lines recently, "How can you compete with Sony if you keep buying their sensors?" (Of course, Tower Jazz designs sensors themselves)
I disagree. The expectations of viewers will continue to rise, and if cameras stopped meeting those rising expectations, viewers would stop viewing content. There would be a collapse of the video production industry, followed by a huge increase in book reading, photoless magazine and newspaper consumption, as well as a drastic increase in other non-media consuming activities such as hiking, boating, rock climbing, etc.
...maybe they should stop improving cameras.
A few years ago, a Canon exec said, "From now on, we'll be making niche cameras". At the time it was understood as a "videocentric" model at a given price point, then a "photocentric" at the same price point, with a similar pattern from the low to the high tier.