Also, in places like NYC where not picking up after your dog is actually illegal, you could have a very interesting time trying to explain to a cop that someone is going to come right away to clean up after your dog. And in the time it takes Pooper to arrive, someone may have already stepped in it, so employing Pooper shouldn't exempt you from getting a fine for the violation.
I'm finding it hard to see how such a business could scale up. If you have a car (which you'd probably need to be able to collect poop quickly over a large area), driving for Uber would probably be a more pleasant and better-paying job. How could Pooper compete for all the employees needed to run this labor-intensive business?