I knew someone who worked at some sort of homeless services clinic, and I asked how many people they were able to help get back on their feet in a sustainable way. The answer was 1; I don't know what the denominator was, but the takeaway is that most of the visibly homeless people you see are uncoachable and you really can't protect people from themselves. With a huge caveat that the visibly homeless is a subset of the homeless/impoverished population.
The implication (given that the US is an outlier here) is that prevention is much better than cure here; that means reform of healthcare and social housing so people are less likely to wind up in that trap.
