That was what was supposed to happen in Oregon when they decriminalized drugs. However, building the treatment centers, shelters, etc took forever, in part due to communities pushing back against these facilities being built in their neighborhoods, and you still need a well-staffed justice system with sufficient judges and public defenders to actually process offenders in a timely fashion or at all. Lack of public defenders, judges and jail capacity is why Portland has so much catch and release, not due to unwillingness to enforce the law.