This isn't hypothetical and it isn't some silly correlation, there are plenty of successful programs doing exactly this, commonly called "housing first". Real estate magically reduces your need for whatever substance you can find to feel relaxed enough to sleep on concrete. Being in the same place every day magically cures your ability to have your medication available every morning. Living in a house magically stops you from needing to wear the same wet socks until your feet peel off. Sleeping in a bed, staying warm and fed and hydrated - all of these make a huge difference to physical and mental health. Do they fix everything? No, that's why I mentioned the supports that need to be added. But they're significant improvements anyway.