"while they step over the clinging-desperately-to-life 'problem' all around them."
The *most* pathetic looking and in-your-face are conmen and criminals. Giving money is a transaction where they sell you a show where you can feel like you've done something good. In reality, you've just encouraged a beggar who fought for that premium corner.
Many of the people with real problems are quieter, and some of them don't even live on the streets. But hey, entitlement comes with believing that being on the street gives you some kind of credibility.
Mental illness is the real problem, and for those who can't fit into the mold of alcoholism, drug abuse, depression or schizophrenia, defiantly homeless should be considered a mental illness. It's certainly not making you or the people around you happy.
Few countries are equipped to deal with mental illness, so people live hard and die on the streets, and that's horrible.