Isn’t the main reason we are bad at these things because we don’t really care for them. I’m not suggesting we are asexual but that we don’t hold flirting etc. in very high regard.
I doubt it. I think it's safe to say that most people pine for social skills if they perceive they lack them. Perhaps controversial, but I'd wager that most of the time resentment towards a social concept like flirting is really just a consequence of defeatism.