See my above post, they are losing marksetshare, if they can't reverse the decline they may just decide to pull out.
Seems like Sony is actually gaining marketshare going into the next generation based on pre-order numbers. Sure, it's early, but seeing that PS3 caught up and surpassed the 360 this generation (coming out a year later, people seem to gloss over that fact, the PS3 has year-over-year beaten the 360 if you look at sales numbers), looking at where the mindset is with the PS4 vs the XBO at this point in all of those polls and pre-order charts (which are all wrong obviously, even if they all show the same exact thing), I think Sony is probably feeling pretty good about their situation going into next gen.
And again, Nintendo and Sony and most companies out of Japan will fight tooth and nail for a position of notoriety for the respect of having tried if nothing else, while a company like Microsoft will look at financials on just about anything and bail on a whim if their previous record is any indication.
I don't want to see a game console go away, just like any product, competing products keep the center in line. But I don't for a minute believe Sony wouldn't go to the mat for the Playstation brand, while I have serious doubts that Microsoft would if it was easier to just abandon ship on it.