yes, it does eventually. as things are not needed anymore you may still see the animals having the instinct, but no real use for it.
they will substitute. like you said, hunting is a good example. we still have that human urge to kill, we dont need to kill in order to survive. eventually i think our instincts will catch up with us, and we wont have that urge to kill..... i hope so. maybe less wars will be fought.
but the point is, nature tends to get rid of things that are not nessicary to survival... well, not get rid of as much as they go away on their own because other types of genetic makeups can survive and reproduce... now this is assuming this uge to kill comes from your genetics. thats dangerouis to say... because you may start accusing people of murder or something because their genetic makeup has a high probability of them killing something... this could be very dangerous if the eyes of the law start checking peoples genetic makeup to see what kind of person they might be. i think this is no good... coz honestly, i think people are the way they are more because of how they were brought up, not their genes... but its nature vrs. nurture. theres arguments for both sides. it could just be very dangerous and deadly to innocent people in court.