Pretty much this. As much as I like a lot of what Sony makes at the highest end, I know no-one else is buying them because they all believe (partially incorrectly I think, but that's by the by) it's overpriced. They're getting killed at the mid-to-low end by Samsung and LG. You can't generate profit from halo products.
I also think that the electronics industry has been turned on it's head in the last 10-15 years. Sony has some very nice TV's in the high end of the market, and always has. Their XBR lineup has been stellar for years(decades, even). But the quality and content you can get now in other brands is unlike it has ever been. Panasonic and Samsung can offer TV's that do about 90% of what a Sony TV does for 75% or less of the price. Most people don't care about that extra 10%.
Same thing with receivers. Onkyo, Pioneer, and Yamaha have been able to place competitive products on the shelves that took away Sony's appeal.
And in Sony's music front...they killed themselves with DRM, proprietary formats, and simply not taking Apple seriously.
The Playstation brand is really the only widely recognized device they have have anymore and that launch and execution was run by a group of chimps.
I've got limited exposure to the Japanese culture/mentality with some medical equipment that I have to support and the front end applications you have to use to operate them. If there's anything I can infer from that experience it's that they are *VERY* reluctant to change and outside opinion. Combine that with the sheer size of their organization and it's hard to be competitive anymore. And then toss in an erosion of your brand recognition and it's really a bag of hurt.
It's really not that different from Apple in the years leading up to the iPod release. But at least Apple essentially focused on one device that was in growing demand, marketed the shit out of it, grew a following and then branched out with a lineup of desirable products that integrated well.