If an early Koolie ancestor was a successful cross between a sheepdog and a dingo, what factor might have governed whether that lineage survived in the breed pool?

Answer

It could have been selected against unless it provided a distinct, preserved advantage

Any genetic input that diluted the desired collie-derived traits, such as herding intelligence, would likely have been selected against by successful stockmen over generations unless the cross provided a specific, preserved advantage.

If an early Koolie ancestor was a successful cross between a sheepdog and a dingo, what factor might have governed whether that lineage survived in the breed pool?
DogbreedancestorKooliedingo