You have to have been in Japan to truly understand just how Sony held nothing back in trying to revive the PS3. There was a time when it was a truly irrelevant system in terms of both hardware and software. Its retail presence and allure paled in comparison to the Wii and DS, which were both at the height of their popularity. The interest just wasn't there for a long time.
Then you have Sony redesigning the system, launching new colors, grabbing third party exclusives, dropping the price, introducing new SKUs, copying the Wiimote and even adopting a new logo all in a desperate, but very well-played attempt to get themselves back to a respectable position. The transformation was truly remarkable. Even the PSP's revival wasn't anywhere near as grand, since it was hardly ever a dead system.
Japan's become a lot less one-sided when it comes to their company preferences. Nintendo will always have its place with Japanese consumers, but so will Sony. I don't think it'll ever be possible for either company to completely dominate this country's game industry. Neither have the spread of appeal nor the resources (such as game franchises) to do so.