Imo it was clear author just want rikuo to be with haru from the start. I came from the anime and couldn't hold the urge so I just read manga. I was really hoping shinako would eventually move on from her past, forget about rou and commit herself to rikuo. Same for rikuo. If only he stopped being indecisive and make it clear to everyone that it was shinako whom he loves. To me, it will be more realistic if they end up together. But sadly the author dragged the plot, shinako didn't really change still doesn't want to grow apart from her past, both of them aren't being honest with themselves and haru ended up winning. Growing apart from your childhood friends is part of being an adult, and the way shinako and rou acted is actually not normal (at least that's what i think). Sure there are people who knew each other since kids and ended up together, but normally it was because they do like each other from start. One sided love can only last so long. Not that i don't like haru winning. It was clear she deserves it. She has been clear to her own feelings from start and actually making effort to rikuo.
In the end, like i said from start, this is all only my opinion. You don't have to feel the same way. But i really think the way the author portrays shinako is not normal. It has been so many years since her crush died and she even went to college, and get a job. How can you not move on from all that? Plus they never even confesssed to each other afaik. Still, the way author made it seem reasonable that rikuo chose haru over shinako is pretty decent. Author really wants to send a message that is if you love someone, be clear, take action and never give up. Just like haru did. Well this is just a manga so ofc it doesn't work like in real life. Meh. 8/10