Dogs think outside is place to poop, and will poop in places they don't know not to. If you live in a suburb or take your dog to a park to poop, it needs to get picked up by someone, because everone has to poop their dogs and that's a lot of freeking dogs.
While I also prefer pooper scoopers (especially given the sheer quanity of poop I clean up on a regular basis) they are somewhat difficult to carry about everywhere.
The obvious answer is the biodegradable bags that are basically identical to plastic, but are made of corn or something. And I am pretty sure they even sell them in special rolls with a despencer that clips to your leash, for pooping and cleaning on the go.
My boss has none of these for traveling with her dogs though, a. Because the plastic ones from the grocery store are still free and legel here, and b. Anatolian poop is a bit to large for those baggies.