Regardless of who/what (more on that in a moment) is at fault for our drug and homeless problems, I would suggest these two are at the top or pretty close to the top of the list of issues which will not only persist, but continue to grow. As a former cop, I have witnessed, over 3o years, both go from "an issue" to a full blown out of control problem. And I sure don't have the answer to solve either.
However, regarding the drug problem, I have seen family, courts, politicians, the user and even the police, drop the ball along the way. Too difficult now (and maybe even back then) to coordinate all those responsible for a sound, appropriate solution. Not only did I deal with the issue(s) as a cop, but from a personal perspective, have a relative that has been a serious drug addict for all his adult life (mid 30's now). He is currently living (if that is what it is called) on the streets, with absolutely no prospect of turning himself around. Sadly, I expect he will overdose some day....
Regarding homelessness, I really saw it increase when our (BC Canada) provincial government shut down all the psychiatric, and drug, facilities and offloaded the responsibility/cost on local governments. Those facilities may not have been an optimal solution but they did provide shelter and care and forced the government agencies to take responsibility. I saw some good examples of persons forced into care, who received enough care to get themselves straightened out enough to transfer into shared/solo housing. That just doesn't happen anymore.
Couple the above with a court system which basically decreed that everyone had the right to a "home", without any support to cope with the outfall. This literally prevented police and other agencies from removing the homeless from local parks and other public places. It is now so bad that there are vast areas, including rest stops, that are over-run with filth, disease and crime to which many citizens no longer visit. And then financial trauma forced average people out onto the streets, with no place to go. Now we have old beat up motorhomes and trailers being lived in on many public streets and parking areas. Again accompanied by garbage and human waste.
And those in charge still have no appetite to spend the massive resources needed to solve these issues. And so, the problem grows......
Man, I got to go lay down now.......