The sensor is merely one component that makes up a camera. It is an important part but without a supporting system a sensor is useless. If there is poor execution in what supports the sensor, ergonomics, accessories, lens etc; the best sensor in the world will not help you sell cameras.
Sony is a huge company and the sensor division is separate from the consumer imaging division that builds their cameras. It has been reported elsewhere that Nikon actual bought sensor from Sony cheaper than Sony internally sold sensors to there camera division because of volume.
So in short expensive sensor tech is paying off for those who buy Sony sensors.
Sony cameras division is in a huge change currently. On sensor alone it cannot compete so it is targeting a Niche market of mirror less with EVF cameras. They have no plans on building a new OVF camera. They initially stated that they could not release a full frame Nex because they lacked the resources to develop the lens to go with it. Now rumors are that one may be available by the end of the year early next year.
So what is paying dividend for Sony? There sensor tech? What is paying off is their partnership with Olympus. Olympus knows how to build excellent lenses, image processing algorithms and compact Image stabilization. Basically they are improving Sony's system.
6D, 60D, Rebel XS, EF-S 15-85, EF 70-200f4L, EF 100f2.8L, Tamron 70-300VC, Tamron 28-75f2.8, Tamron 150-600, EF 40f2.8, EF 50f1.8, EF 85f1.8, EF 24mmf2.8IS EOS M 22f2, 18-55, EOS M-EF adapter, Nex6, A7II, SEL50f18, SEL1018, DN 30f2.8, adpaters and Fd and M42 lens.