I'm not quite sure what Sony's focus is going forward. Obviously their historic strength has been in consoles, but I believe Sony (And others) are correctly identifying the mobile gaming market as the sector for growth long term. I do not think, for example, that the PS4 is likely to sell more units than the PS3 did (although it will hopefully do so at a profit, rather than a huge loss), but I can most definitely imagine a mobile successor to the PSP selling significantly better than the original PSP did.
The PSVita is apparently not that device, but that doesn't mean it isn't possible. Essentially what I'm saying is that I wouldn't want to be cornered in to the console gaming sector at this point. It isn't dying, but it certainly looks stagnant -- while PC continues to evolve, tablets are growing, and other mobile devices are growing, too.
I got the impression that Sony sensed this too, but they're not doing a very good job of escaping this box.