why are we paying people's rent, when we could be building lots of shelters? i dont know the costs involved,
Well, there's the rub. It turns out that paying a fair market rental fee minus 30% of the renter's income is far cheaper and allows for much greater upward mobility than simply warehousing people in large public shelters. Large public shelters look cheaper in the short term but shelters tend to concentrate and increase a lot of social problems- disease, assault, rape, theft, drugs all go way, way up when you put a lot people together in a public shelter. Concentration of social problems is then magnified by community resistance to such shelters. As much as govts try to spread the shelters out, each individual target community fights back hard with the result that homeless shelters tend to concentrate in one or two parts of town, creating little communities of concentrated social problems.
According to experts opinions like Colorado Coalition for the Homeless, just the cost of managing the increased social problems created by shelters exceeds the cost of paying rent for that population.
Here in Denver, the number of available shelter beds has far exceeded the number of people sleeping out of doors for better than 20 years. The shelters never fill up except when it is very wet or very cold because the majority prefer sleeping outdoors to sleeping in a shelter. Bedbugs and lice are endemic and without unless policed constantly, very noisy, disruptive, even violent.
70% of the 5 million recipients of section 8 are unemployable- elderly, children, and the disabled. Most of the remaining 30% are taking care of that 70%. The public cost of exposing millions of elderly, children, and disabled people to all that disease and disorder and then trying to treat all the new problems created (when any good doctor would first recommend isolating and securing these vulnerable populations- preferably using some spread out, well-managed, and cost-effective solution like section 8 housing) far exceeds the present solution.