I know it's almost an oxymoron, but homeless is closely tied to housing prices.
If you lost your job how long would you be able to keep living where you are? Maybe a long time, but for maybe 10% of the population it's a much shorter frame. Add on some other twists of fate (or bad planning): a medical emergency; an abusive spouse; an unplanned pregnancy; a substance abuse problem; and you have a concoction that could land you on the streets in a few months if not weeks.
The "free drug paraphernalia" (e.g. services to help save addicts lives) has followed the wave of addicts, not the other way around. People were dying long before they showed up.
Affordable housing, shelters, and housing first programs are the real keys to solving this. But there's a lot of people who would rather eat their right arm than see a drug addict (or other undesirable) get government assistance.
NYC is a classic example of a US city where homelessness is less visible because they provide shelters and other public services. That is NOT to say that homelessness isn't an issue there, it 100% is. Its just that it looks different than in, say, Seattle.
Europe (in general, though it varies) also has a large percentage of it's homeless population sheltered.