That is an interesting question and one that can't satisfactorily be answered until much more research is done. There are conundrums. Again, it is estimated that 21 million people tried cocaine in 1988. Yet, of those, only 3 million currently use it, and only a small percentage are addicted. As for crack, it is estimated that 2.5 million have used it, while only a half million say they still do, and that figure includes the addicted and the casual user.
Some reports claim that as many as one half of crack users are addicted.
As I have said, crack is cheap, and for that reason may be especially attractive to the poor. We don't even have reliable data to tell us that crack creates a greater rate of addiction than, say, cocaine. My own guess is it doesn't. Remember that the drug acts on the same brain systems that cocaine and amphetamines do. Now, presumably, an educated person, concerned for his livelihood, wouldn't take a revolver with nine empty cartridges and one full cartridge, aim it at his head, and pull the trigger.