The only thing I will add to that if it helps people make a choice is, if they take the dog to the shelter it will be guaranteed food shelter and medicine where needed, if it has a serious problem it can be sent to a veterinary where it can have the relevant treatment which is not currently available at the shelter or if it has a serious illness it can be put to sleep in an absolute painless manner, if the dog is fit and heathy it has a fair chance of finding a new home. If the shelter think the dog would survive on the street it can be neutered, inoculated, tagged and put back on the street.
If you leave it on the street there are no promises.