If 60% have moved to "a better situation", does that mean that 40% went back to being homeless after their 10 months? That doesn't seem like much of a success.
Even though the rest stops don't turn away the "hardest cases", there are probably a lot of homeless people who choose not to apply for a spot in a rest stop because they are unwilling or unable to give up drugs, including alcohol. One thing about Whoville was that alcoholics were allowed to stay there, and most of them were doing better at Whoville than they were doing on the streets.
Claiming that the "social environment" at Whoville inspired the rest stops is not quite correct. Whoville was based on the concept of people getting together and taking care of one another without "social engineering". The residents showed that it was possible to set up a fairly stable environment without social workers. 
Its one flaw was that the city was totally against the concept of self reliance and forced people to be dependent on charity.