Adoption through the foster care system costs nothing, daycare is free, Medicaid until age 18, and you get a stipend monthly (~500) until child is 18. My grandson was adopted this way. Money stops very few from adopting.
But wanting a straight from the hospital newborn healthy white baby with no fear that the foster situation will end with the birth family getting the child back us —- that is what stops people from adopting because that route is expensive. Foster to adopt has more uncertainty but it is not expensive and nearly all costs are covered.