In the homelessness example, it's not so much that the programs and groups want to justify their continued existence (though that might be happening too). It's that the programs themselves incentivize more of the problem. When they give things to homeless people, such as food, shelter, clothes, social services, even needles and a "safe place" to get high in some cases, and often with few or no conditions, they make being homeless more tolerable. Word gets around, and people who could not feasibly be homeless where they are are drawn to Portland because they will get more support there.