Although Sarah Connor managed to survive the events of The Terminator, it came at a cost. Kyle Reese died protecting her from the T-800, meaning that they would never grow old together and John Connor would never know his father. But this wasn't always the plan. According to co-writer and producer Gale Anne Hurd, executives were gunning for The Terminator to end on a happy note, with Kyle and Sarah still together. Hurd recalled:
We got notes to end the film before the end of the film. Not even have The Terminator rise out as the endoskeleton, but just end with Kyle Reese and Sarah Connor hugging.
So if these executives had gotten their way, once the T-800 was caught in that tanker explosion, that would have been it. The climactic scene in the factory wouldn't have gone down, and Kyle would have survived and lived his life with Sarah, presumably with no more worries about Skynet rising to power in the future. That's nice for the characters, but it doesn't make for nearly as compelling a resolution to the story.
There are also more unsung heroes which is that one of our strongest supporters was the head of the completion bond company, Film Finances here in Los Angeles. The late Lindsley Parsons Sr. knew what The Terminator was going to be. Roger [Corman] knew what The Terminator was going to be and not a lot of people did. You absolutely need people to believe in you. You also need people to tell you when you're screwing up that you can listen to. Lindsley was all of that. Roger has always been all of that, but we could have bowed to the pressure. Or, we could have been wrong and not listened to the things that made the film better. Luckily we had each other's backs.
As popular as the Terminator franchise is, it's definitely a bleak one. With the exception of Terminator 2: Judgement Day, all the movies have ended on downer notes, with audiences knowing that Skynet is either still coming or sticking around. The Terminator naturally set the tone for its follow-ups, and if things had ended well for Sarah Connor and Kyle Reese, not only would we not have seen Sarah destroy the T-800 for good with that hydraulic press, who knows if the movie would have even spawned sequels.
Fortunately, things worked out in the end for The Terminator, and seven years later, Terminator 2: Judgement Day told the next chapter of this science fiction saga. Fast-forward to now, Terminator 6 is currently shooting, but instead of following the events of Genisys, it will be a direct sequel to the first two Terminator movies. Arnold Schwarzenegger and Linda Hamilton are reprising the T-800 and Sarah Connor, respectively, and the new cast members include Mackenzie Davis, Gabriel Luna, Natalia Reyes and Diego Boneta.