Disclaimer that I personally do think Olivia's song was inspired by Taylor's a little too close for comfort. But obviously what Taylor did with imgoingtogetyouback was even closer and it's hypocritical not to see it.
But yeah, on your overall question/comment I worry that Taylor might grow bitter as she gets older and could be mean to up and coming artists. And partly it'd be the fault of the media and show biz environments. They're always pitting women against each other. And like Taylor writes in Clara Bow , they're always saying to the new kid "Oh you're the new version of X big artist, but prettier/sexier/edgier/cooler". That's going to be hard for anyone.
But Taylor in particular seems ill equipped to sustain an actually permanent fall from the top of the pyramid. The Rep era wasn't the huge fail she likes to paint it as. Maybe it wasn't the acclaim and universal fanatism she has now, but it wasn't quite a cancellation or anything. And she came back stronger so she has this chip on her shoulder of, I'll only come back harder if they ever push me again. But what happens when she eventually doesn't? She can't remain this big forever. It's unsustainable.
And also, with how obsessed she is with marriage and babies, if she goes and does that and still tries to hold on to her present levels of fame it's going to be a shit show of epic proportions which will make her even more bitter.
So yeah. I can totally see her as an 80 year old still feuding with Kim.