When you take say a veterinary tech program or a dental hygienist program or any other degree program in a field that requires licencing after graduation your degree will not be recognized so you are therefor throwing your money away. As for lower education most colleges will not accept a high school diploma from an unaccredited school.
If you go to a college that is not regionally accredited and graduate your credits will not transfer to another college of your choice to earn a higher degree. You must then start over and retake courses which means more money. These colleges that are not regionally accredited are thinking along the lines of short term goals rather than long term goals which is continuing their education to earn a higher degree!
They may not be the best options for advanced education, but does that mean that the opportunity shouldn't be there for someone who desires to use it? If there are people that choose to use such an institution, then who can say it shouldn't exist? If no one uses it, then it will fail on its own.
A good deal of schools lacking accreditation are religion-based and while not everyone agrees and it could prove costly to a student later, in transfer, obtaining a job or even with critical thinking skills, it is hard to say these schools have so little to offer that we should rid the world of them.
As long as the students attending know the school is not nationally accredited, there is no issue. Not every student is seeking an accredited school, and they should be free to attend any school they wish. If there is no deception going on, and the students are aware that their credits won't transfer, there is no reason not to let them stay open.