Look me in the eye and tell me they’re not a couple in that scene. Like, the subtext is really, really strong. They arrive at the castle together, bantering and bickering like an old married couple. I mean that mostly in the physical proximity sense, but there’s something there.
And when we finally catch up to Applejack and Rainbow Dash…they’re together. But then we got to the series finale, which involved a jump to the future to see where the characters end up. It just didn’t happen, especially not between themselves.
The Mane Six didn’t have romantic partners and rarely, if ever, even had crushes or infatuations. Romance was never really a thing for the main characters in My Little Pony: Friendship is Magic, which ran for 10 seasons between 20. It depends on what you want to read into the context presented. Rainbow Dash is giving off major Big Gay Aunt vibes, right?