I agree. In fact half of the couples in chapter 700 didn't make sense to me. My point is that it was established that kakashi was desirable prior to chapter 700 so I'm a bit surprised that he didn't end up with anyone when people like kiba, who isn't as desirable, are ending up with people. I imagined that kakashi would be more likely to start a family and that people like kiba would be single.
Because he let Rin die. U_U