Sony makes a huge portion of their revenue off lawsuits. They possess a ton of intellectual property, execute questionable legal tactics, and have comparably few actual assets. That said, they have no case here. They left a huge gaping hole in their system that could be exploited by knowing a simple pair of values. There's nothing illegal about enabling someone to become enabled to pirate or to modify a system. That's fully protected by first amendment rights.
Hacking the PS3 changes just about nothing about the economy of the PS3. Piracy doesn't hurt the gaming industry because it doesn't alter the value of total demand. In fact, it pressures the industry to keep prices reasonable by not exceeding the value at which most consumers will seek a more cost-efficient alternative. Sony's just butthurt because once again they've shown themselves to be less capable of a computer entertainment distributor than Microsoft and Nintendo now that every system they've ever released has been hacked.