The manga had nowhere to go after the Miku becoming a third year and having to study for exams and all. It would be super monotonous and forced if she kept pestering Yabechi in her last year when she already has a goal fot after she graduates, then she can try to get together with Yabechi.
I can feel that the editor pressured the mangaka to rush the ending. It was a good ride, even if it was a short one.