Technically she isn't a love interest at all, because the MC doesn't really seem interested in her in that way. She was a needed ally for "Minori" to stay hidden.
Also this would be far from the first Manga, that has side-Love-interests, that never really had a chance. Actually that's a big Harem-Manga trope.
And several other girls, including real members had a crush on him too. ?
But as said before, Minoru/i is representing the fans of AKB and as such he has to be loyal and unwavering support of her, no matter his chances on actually getting her. (just like a real fan can't get the Idol either ?)