I like where you're going with this and it really touches on what I think the show is about.
The show is about Star growing. Star is in the name and it's basically the entire premise.
Marco has become a very important part in the show as well, so important in fact that I can't even begin to imagine what the show would to if it were to separate them for a long length of time.
Jackie, really only comes into play as yet another way for Star to grow. Where this necessity to grow and deal with those problems takes her, we can't really say.
So in the sense that the show is actually straight up about Star and Marco, Jackie, kind of becomes cast in this "Only another reason for stress and strife between the two, so Star and Marco can overcome it." light.
I can't imagine Jarco lasting past S3. Or maybe past S4. Starco is kind of IN the show.
Maybe Star has to learn to grow out of her crush for Marco . Maybe it's Marco who has to learn the pros and cons of both relationships and choose.
I'm just super pro Starco right now and I'd have a difficult time adjusting if Starco wasn't end game. I am very biased. But then again, I might be right. But again I may be wrong.
Either way, I just think Starco is cute and perfect, man.