Housing is just one aspect. Food, medicine, paying for employees (social workers, security, medical staff) etc. But even if say 75% of that was for housing it’s not easy to just say rent them apartments; first off not enough apartment buildings are willing to take them in. It’s difficult to even find cheap motels that will work with cities to temporarily house the homeless even though it’s guaranteed money. Cities are looking at building shelters but then it’s NIMBY time. Without dedicated facilities with mental health, addiction, etc treatment which the US doesn’t have homelessness will be a forever problem.