Um, no. Why would it be their responsibility? There are laws regarding IP theft. If you willingly break them you can't just say "well your security wasn't good enough".
Apple is obviously the victim but prevention is easier than what is happening now, which is potentially going to court, discovery, etc.
There's really no way to prevent an employee from taking a piece of paper or a digital file from one place to another. The most you can prevent is accidental transfer. If they are malicious they will find a way no matter what guardrails you put.
And they can get you for theft, etc, if you do. Sometimes the social and legal controls are far more effective.
If you leave your house unlocked and someone steals your stuff AND is never caught, you're SOL.
Okay but why assume the latter part? In this case the perps were clearly caught.