Only Sony is in any real danger of abandoning the console market simply due to the state of the larger Sony conglomerate, but the playstation brand is as strong as ever. Microsoft, meanwhile, has shown itself to be content to lose enormous sums of money for the Xbox, treating it almost more as a pet project than a money making endeavor... The Xbox is the cool face of their company that they'd not otherwise have.
Even if Nintendo's next console proved the most popular in the next generation I don't think either of the other two would be forced out. The possible exception is if Sony was in dire financial straits and really laid an egg or if either Sony/Microsoft decided to forgo a full console next gen and simply release a streaming device under the Playstation/Xbox name (Sony does seem potentially headed in that direction).
There's room for all three, essentially... The market has grown since the days of Nintendo/Sega.







