> Wouldn't there be basically no dogs left in a couple year?
You may be amazed how many people don't see pets as responsibilities and either discard them for trivial reasons (like moving house) or let them breed and then dump the litter out to fend for themselves.
Yeah, joking aside I think pet registry has to be the other side of this + enforcement with DNA tests. If you have puppies, and they end up as strays, there should be sanctions.
Depends how affordable DNA tests are. For a developing country, sterilization and vaccination might be cheaper than tracking every stray dog to their or their parent's owner. Policy can also make this infeasible if, for example, dog registration is too expensive in the first place for owners.
>Wouldn't there be basically no dogs left in a couple year?
No. Plenty of people still won't sterilize their pets and abandon their litter in the street or some just run away or are lost or abandoned by their owners, therefore the stray dog population will never be absolute zero.