The Terminator is Death. It can’t be defeated, only postponed.
In the first movie: the Terminator comes to kill Sarah Connor before she can reproduce: the only way for a part of her to avoid Death. The Terminator is defeated only after Sarah Connor is impregnated.
In Terminator 2: Death returns for Sarah Connor’s offspring, despite her best efforts to protect him. John must accept his own mortality by sacrificing his own protection from Death, bringing John into adulthood.
In Terminator 3: John Connor teams up with a potential mate, but realizes that he cannot defeat Death, and embraces it instead. It’s the least popular movie because it rejects the wish-fulfilment endings of the first two and embraces the reality that the future is set: everyone will die eventually.
In Terminator: Salvation, McG has Batman fight Transformers.” —Comment posted by TheClaw on Metatalk.