The area around them was blighted and isolated- no community playground, parks, or shopping areas like a typical neighborhood. The community’s medical needs were addressed by pop-up clinics run out of a van

This also completely applies to areas of USA with less population density. Even for people with jobs.

Remote Area Medical (RAM) is a nonprofit provider of mobile medical clinics delivering free dental, vision, and medical care (as well as veterinary services when available) to under-served and uninsured individuals.

Founded by British philanthropist Stan Brock, it was originally conceived to treat people in the developing world, but turned its attention to those in need of health care in the United States