I'll admit I have heard Cruz say he wants to retire a Giant. But I think there is a difference between planning and wanting. Paired with the fact that Bennett has also said he would consider taking a discount to stay here.
I'm not saying that Cruz isn't as selfless as Bennett either, it could just be a case of Cruz's management having him stay a little more tight lipped than Bennett's.
Either way, Bennett has had an opportunity to see the grass on the other side, Cruz hasn't. I believe it's affecting Bennett's approach to this considerably.
Cruz and his handlers are very wise not to discuss any details in public. Cruz has expressed his thanks to the Giants any number of times. It remains to be seen if he will be a Giant of the future.