The precedent has already been set in the US. Apple lost it's battle against the jailbreak on the iphone which allowed EXACTLY the same thing as this jailbreak for the PS3. I HIGHLY doubt they will win.
As for why they are dumping all this money and effort into lawsuits may be based on creating an iron fist for later releases. Think about it. The average lifespan of a console is 5 years. The PS3 is very close to this and soon, maybe a few more years, the PS4 will be announced and released.
They probably got so confident with the security of the PS3 that they have put the same security measures into the architecture of the PS4. IMO they are trying to set precedence so they don't have to go back and possibly redesign the PS4 hardware and security. It is just speculation but it is highly plausible and makes since. This is the only reason I could see why they would try and "make an example" out of people even though it is already out.