I appreciate the discussion of temperament in terms of understanding someone's degree of flexibility, but I question how fixed most of the aspects of temperament truly are. For instance, I could understand limited adaptability as a kind of defense mechanism in and of itself, as opposed to something you're naturally born with. Though I agree that everyone has some level of adaptability that they are born with as babies, I would think that environmental factors can greatly effect whether someone becomes more or less tolerant to unscheduled change, or the ability to "roll with the punches."
Similarly, with distractibility, we have heard many times that something like ADHD can be caused by environmental factors, and even biological factors like lack of sleep. Impulse control, I would argue, is definitely correlated to environment on some level, and it seems that lack of impulse control could be considered a coping mechanism. Maturation is often understood as the control of one's impulses, especially in children, as they learn the repercussions of their actions. I think that discussion of temperament provides an important perspective, but should basically be considered fluid over the course of one's life as opposed to fixed.