Let us be positive about this. The government are also putting mentally to the next generation that the drugs must stop at all cost, so in the future if Duterte finished his term, the war on drug will still continue.
You need to understand why people use drugs. People resort to drugs, to substitute them for painkillers and alcohol. Sometimes, it is an avenue for them to escape from despair and hopelessness. If drugs such as meth are not available, then people will start using some other homemade drug. And in most cases, these new drugs will be even more dangerous than the old ones.