I live in the countryside and there lots and lots of dogs. But no dog walkers. All the dogs in the village, 30, 40, maybe more are free to roam. And just like @KhunLA says, the dogs will always make their deposits very discreetly, never on the roads. I walk every day but I never encounter dog poo and I doubt if any Thai would consider removing it if they did. They don't even clean up buffalo dung for heaven's sake!
This doesn't answer @stoner's issue of course, but it does at least indicate the type of society that we're dealing with here. Scooping up after ones mutt is a fairly recent western construct, which I doubt will ever catch on here.