In your quote he is not saying he didn´t make any effort. Is him recognizing his efforts (like the dates they had in middle school) were useless and didn´t reach nothing with Hikari, is precisely him recognizing he needed have more initiative and being more "masculine" to be able to "stand beside Hikari" is first place and make her finally see him as a boy and not as a little brother.
Is the moment when he realizes Hikari doesn´t want the dommy girlfriend of nobody and she is as passive as him or even more.
Though yes, I agree w/ you that a major reason Yuu went for Yami is that he had to put in 0% effort there.
Not, Yuu did really put a real effort with Yami. Over all when he comforts her and they hold hands in the love hotel when Ayami is crying. Being submissive doesn´t make him an useless bag.
But yes, Yami is the dominant and active girlfriend who Yuu always wanted and totally disposed to carry the pants in the relationship. She loves dominate him and he loves being dominated by her.
This is the reason why Ayami is fully right about Hikari doesn´t know who is the real Yuu Takamura. This is the reason why they would became a couple in any case, Ayami abussive step-father only fastered the process.
Without these themes of role reversal / female domination, is almost impossible understand Yuu - Ayami relationship.