Not exactly, hence the rise of fentanyl. Prior to the rise of fentanyl, new addicts often went from prescription pills like oxycodone to heroin as their lives unraveled because prescription drugs are expensive and hard to get. Some enterprising drug dealers started enhancing their cut heroin with fentanyl which can be imported from China and is extremely dense compared to other opiates, which matters because smuggling is most of the cost. Downward pressure on the prices changed the ratio until you were left with pure fentanyl, so in effect prescription pills were not available enough and drug dealers were able to capture the market with more dangerous but cheaper product.