A person might look at it this way. If, I am reactive and looking for a place to lay blame. I am probably going to blame genetics to escape any accountability and wash my hands of the problem by culling the cow. I will not use her genetic line, even if there is a huge advantage to her gene pool, because I am positive that everything wrong with her is heritable and can't have anything to do with her environment. The fella that has the same line and has a nice manageable set of cows is just an exception, because I tried them and they didn't work.
If, I am proactive and an optimist. I will try to step back and find away to solve the problem. When I run into the occasional cow that I can't change, I have to accept defeat and haul her to town. Trying the whole time to decide what I might have done differently to change the situation, knowing full well that there are some things you can't change.
I guess, it maybe heritable. I think it is much like a child who grows up with a poor home life full of abuse and disappointment. In turn as an adult uses their up bringing as an excuse to act the same way. It only takes that one significant influence int their life to turn them around. Life is what you make of it, so is your ranch and your cowherd. I honestly know very little of genetics or heritable trait. My advantage is not having any preconceived notions of any particular line. I guess ignorance is bliss.