PrimeSense provided a low cost chip, but Microsoft:

- did the product design and put it into a friendly package (take apart a Kinect some day, they did some neat stuff in there)

- developed the body tracking algorithm (http://research.microsoft.com/pubs/145347/BodyPartRecognitio...).

- developed the microphone array, speech recognition algorithms

- provided developers the resources they needed to take advantage of the device

- applied it well to gaming and quickly brought it to market

- put the technology in the hands of millions, triggering even more innovation