The romance is non-existent anyway, all the romantic moments get overrun by dirty jokes or other happenings. The girls are all shy virgins so they are never going to confess. Tsuda hasn’t taken any hints so he isn’t going to be making any moves anytime soon. Also, haven’t some of the third year events repeated already? I think the author will just keep it going for as long as he wants, it’s his dream dirty joke filled work where he can keep drawing 4-komas and make people happy. After 3 works with dirty jokes, I don’t think he will start a romantic relationship between any of his characters.