It actually does in several respects. You didn't capture the homeless working class, the homeless social security / retirees, and the folks with physical disabilities (you only brought up mental illness). The comment you have made in my opinion vastly overstates the drugs and mental illness aspects and vastly understates the number of people that (1) work at regular jobs and are still homeless, (2) the number of seniors that are homeless, and (3) The folks with physical disabilities, for example chronic physical conditions.