the thing abiout the shojo comparison though is that most of those ALWAYS show development in small doses sometimes large doses
take a movie i just watched call A Silent Voice. the MC as a young child bullies the MFC a deaf girl and does so in some trully heinous ways. But it shows him slowly grow and change as he realizes what hes done to her. And as the movie progresses he makes amends. the relationship between the two progresses in a visible manner from start to finish where one can trace it easily
SS has no such progression. it simply is stated that Sakura is in love with him and it never advances anywhere from there save an awkward apology and a forehead poke and we the audience are meant to construe this as true love especially after Sasuke outright stated he had no feelings for her whatsoever