Opiates are also a fun and addictive drug. As long as they exist and are generally available, some percent of the sub-population will abuse them. We can try our best to keep them only for medical use, but once the prescription leaves the pharmacy there's not much you can do. You can't blame the legal manufacturer when that happens, if they took all required steps to keep their drugs in the legal channels. Maybe you think that's true, but that the opiate manufacturers have used their power and influence to over-prescribe their products. That assumes that opiates are over-utilized in American healthcare. And that's a narrative that simply isn't borne out by the data.
Only 0.19% of opiate-treated chronic pain patients without a prior history develop any form of abuse or addiction[1]. And remember these are chronic-pain patients who take tolerance-escalating doses over years or even decades. Virtually no one develops an opiate addiction from following their medically prescribed treatment regiment.
The death rate from prescription opiates has not budged since 2006[2]. The vast majority of opiate overdoses in America are not prescription opiates, but illicit fentanyl, and to a lesser extent heroin and methadone. Nor do chronic pain patients face any major risk of overdose. The fatal overdose mortality rate for long-term opiate-prescribed patients is 17 per 100,000[3]. And that number doesn't exclude the subset of the population engaged in abusive behavior like mixing with alcohol, snorting pills, or hoarding medication.
Finally the sizable majority of prescription drug abusers in this country do not source from a doctor or the healthcare system at all. The vast majority get their drugs either from the black market or a friend or relative. On the National Drug Use Survey only 18% of prescription drug abusers report doctors as their primary source. And among street prostitutes (a high at-risk group) only 5%[4].
All of this goes to show that there is very little evidence of any sort of over-prescription of opiates in America. To begin with the vast majority of the opiate crisis has to do with fentanyl, not prescription drugs. But even when it comes to prescription drug abuse, the intersection with medical users is vanishingly small.
However what there is a major problem in America is untreated chronic pain. 50 million American suffer chronic pain[5]. And 20 million suffer high-impact chronic pain which severely impairs normal life function. More than 10% of suicides are linked to chronic pain[6]. High-dosage opiates are absolutely essential for this group to live any sort of normal life. As long as there are such massive numbers of legitimate pain patients, the law of large numbers guarantees a large supply of diverted opiates. Even under the tightest controls. There's simply no way around that except by denying most of the legitimate patients treatment for their debilitating conditions.
[1] https://www.ncbi.nlm.nih.gov/pubmed/18489635 [2] http://www.ncsl.org/portals/1/documents/health/APeeples0118_... [3] https://annals.org/aim/article-abstract/745518/opioid-prescr... [4] http://sci-hub.tw/https://www.tandfonline.com/doi/abs/10.108... [5] https://www.cdc.gov/mmwr/volumes/67/wr/mm6736a2.htm [6] https://www.ehidc.org/sites/default/files/resources/files/Ch...