A kelpie is reckoned to be the worth of a worker on the farm or two backpackers. Farms are bigger, flocks larger and well nigh impossible to work without a good dog. There are paddock dogs, yard dogs and some that are good at both. A dog that can load four decks of sheep or muster a flock out of a 200 acre paddock is incredibly valuable. They keep a constant flow of sheep up to the shearers. Pity help a rouseabout who mistreats a dog. Some jobs like crutching trailers need lots of dogs. Dog men get $45 an hour on trailers. Some of the highest prices paid for dogs are by stock transport operators.
The modern safe replacement for the quad bike is the side by side at over $20000 and you'll spend a frustrating time trying to move sheep with one without a dog.