Shizuka's done nothing wrong. She's not blowing off Keisuke. She didn't know or expect that he planned to ask her to walk the festival with him because he has pussyfooted around and hasn't said anything to her. If he had asked her and she agreed THEN going with Irie instead would be blowing him off.
the only thing she's done wrong is not be romance-coded as the ostensible FL of a romcom manga.
She only cares about her big HS Debut. That's her whole deal. Keisuke went and caught feelings, and now his problem is that he waited too long and was too helpful to her, so she's making it big, fulfilling her character arc, and she was written to be so perfect that she's now lapping the other characters on the Narrative Race Track - meaning Keisuke is falling so far behind that he's likely not going to be able to catch up and actually get her to notice him romantically, or get her to
look at him romantically, until he takes the time to work on his own debut and issues.
Which, I suspect, is where both Hebikawa and Otobe come in. The former because she's a big part of his trauma and arc toward succeeding his debut, and the latter because
she is an in to Kusunoki as a childhood friend, and also likes Keisuke, thereby potentially giving him romantic experience (or more trauma, jury's still out on that).
Until Kusunoki stops being self-obsessed (not a bad thing, but she only cares about her own needs at the moment and not Keisuke's), nothing's gonna work for Keisuke.
Maybe if he gets involved with either Otobe or Hebikawa in the coming arc, Kusunoki might look back, realize he's not there at her side like he has been this whole time, and get lonely/jealous or something.
She's the FL, this is a romcom, I'm not going to be dumb and pretend the author's gonna pull a fast one and
not make her the winning heroine alongside Keisuke. But as of right now, she's sidelining herself in the romance department until further notice.
Keisuke's at fault for not taking the chance when he had it. But I suspect that even if he had, it wouldn't have progressed any romance between them, and honestly might have discouraged him even more when nothing came of it at the end.
