OP never said you can't develop conscientiousness, just that it was almost certainly partially genetic. You can learn to run faster, but some genetic profiles will never make it to the Olympics by just practice.
"Be hard to compete with" is also not bad advice, at all. What it really boils down to is, start learning to do something that takes a long time to learn now, and once you know it, you'll be ahead of the people who are starting then. And once you've done that, start learning something else that takes a long time to learn.