What type of “ghost” business in your area has been around the longest & always seems lacking enough customers to explain its being in business?

All the “ghost” business I can think about right are doing fine in both the legal and illegal products. Like those bars where they sell (or allow to sell) drugs. That probably happens with more serious crimes, like with transportation companies for example. But my point is that if the “ghost” business is lacking costumers, then that’s suspicious so it’s a failing “ghost” business.