So huuuuh... Why aren't they dating yet?

My guess: because Wakaba liked a boy once and Komaki thinks Wakaba is straight.

I've been thinking it was this for awhile now, since Wakaba liking a boy was apparently the trigger for Komaki becoming the way she is toward Wakaba, and I feel like the most recent chapter is practically confirming this.

I guess Komaki has never heard of bisexuals, or just been told that a person liking someone of the opposite sex one time doesn't mean they'll never be attracted to someone of the same sex, but I guess if she had this manga would've ended in the first chapter lol.