Is the war on drugs in the US enabled greatly by citizens?

Is the main reason why the war on drugs in America can’t be won is because too many people can’t function or entertain themselves sober and without drugs? If people wised up and stop buying the stuff the drug cartels would have no customers and if there is no profit in it would not have the interest in smuggling all that dope here. If there was no demand why would there be a supply?