"All guys like that sort of thing!" -Kabakura, about Childhood Friend Lovers
I don't know about that. Maybe in Japan or Asia in general there's that general notion, but here in the west, they'll choose the hot sexy girl over the childhood friend any day of the week. It's also interesting that Narumi is willing to date Hirotaka, as a relationship of convenience. No female in the west will date someone they aren't attracted to, just because he is her childhood friend.