The only group that can be counted on to consistently buy new hardware generation after generation are gamers. This is the group Sony went after first and foremost.
Nintendo strayed first and it paid huge dividends for them in the short term. However, their new audience had zero loyalty to the brand was not interested in upgrading.
Microsoft strayed with Kinect and ran into the same situation as Nintendo. They also strayed with their reveal by focusing heavily on television capability.
Sony made PS3 gamers happy run through the end of last generation and they began this generation by focusing on that same demographic. They did the best job (or least worst job) of convincing gamers that they are the priority. This instilled product confidence.
Placing your core audience first leads to steady support. Going after other audiences might produce spectacular results if you can get a hit but it can also backfire and leave you playing catch-up.
