A similar model is being followed in Europe where the unemployed, disabled, recent mothers and the poorer people are provided some sort of basic support by the state. The higher earning people have extra cash to live more comfortably.
It's really not an easy problem to solve. Ideally everyone should be guaranteed that they get enough food and a place to live, with anything extra being their own responsibility. But this is hard to implement in practice.
Good government must manage the leech/liar problem. Such people should not be enabled.
"I don't think that leeching lies in human nature"
I think many thousands of years of human history proves this statement false. Leeching is one of the core components of human nature. Businesses (or governments) that take this into account will be successful. The ones that don't will fail miserably.