Series finales have that responsibility to leave you feeling good about entire series. You want to feel like the viewer closes the book satisfied. And if you strike out on the finale it skews how you feel about the entire series.
When I go to a music concert, I don't say, "My purpose is to get to the end and enjoy the finale. " If that were the purpose, everybody would write finales and nothing more. The purpose of the concert is to enjoy each note as you go along.