Sony isn't going to be in trouble next gen for these reasons:
-The PS4 will likely be more powerful then the Wii U at launch, so 3rd parties will flock to the PS4 and give the PS4 the best version of games just like they are doing now.
-As long as Sony can make good sequels and new IPs each gen, they won't need to have a huge system seller. Keep in mind that, while Halo and Mario can carry a system, Nintendo and Microsoft don't make as many new IPs each gen as Sony does. Even if 3rd parties abandon Sony next gen, they can carry themselves with new IPs and other games and stuff. Sony has 14 internal studios. It's not like they can't deliver a steady flow of PS3/4 games when the going gets tough.
-One last thing, unless Sony fucks up catastrophically with the PS4, the 3rd parites will still be there. That alone will help Sony.
