It's sweet that Nagatoro wants to get Senpai keen on the idea of getting drunk so that they can go hang out whenever they grow up, implying that she wants to be with Senpai after high school. Of course, Senpai is under the assumption that it would happen with him and Nagatoro maintaining a senpai-kohai relationship. We all know that Nagatoro, whether she wants to admit it out loud or not, wants to go be more than that with Senpai.
Also just because the main characters are not together, doesn't mean there's been no progress in the story. Progress is not determined by the character's relationship status, it's determined with how the characters have developed. If you compare how Nagatoro and Senpai acted individually, as well as with each other, in the first 5-10 chapters and compare that to how they are like in the from the start of the festival arc to this chapter, you will definitely see a significant amount of development, even if the two aren't an official couple, despite the fact that they act like a couple and everyone around them basically assumes that they are a couple in all but name.
