Yes, most public figures have the financial resources to hire high-priced lawyers and keep themselves out of the criminal justice system to get their treatment. It would be much more difficult for the average non-famous addict to do the same. I would think most of them would be hesitant to come forward and admit drug use for fear of prosecution.
There are plenty of drug and alcohol addiction specialty hospitals that treat "average non-famous" patients. The cops don't arrest patients entering or exiting.