heroin vs. oxycodone

I found out that heroin was synthesized from morphine, which is naturally substance of poppy plants. I know it was used as pain remedy and commercially marketed. But I don’t know why it came, when heroin is highly addictive drug. Isn’t oxycodone used the same way, but maybe is a little bit better? Why everyone doesn’t stop use this drug that is considered the most abused and start with oxycodone?

Heroin can be injected, smoked, or snorted. Intravenous injection produces the greatest intensity and most rapid onset of euphoria, which can be felt in 7 to 8 seconds. Even though effects for sniffing or smoking develop more slowly, beginning in 10 to 15 minutes, sniffing or smoking heroin has increased in popularity. That happened because of the availability of high-purity heroin and the fear of sharing needles. Also, users mistakenly believe that sniffing or smoking heroin will not lead to addiction. Problem is that oxycodone has similar effect as heroin. While most strong pain medicines last only about four hours, oxycodone gives a steady 12-hour release and has fewer side effects. But to addicts who chew the pill or crush it and snort or inject the powder, oxycodone produces a quick, heroin-like high that can kill. In areas where abuse is prevalent, some doctors say they worry that even patients who need the drug might be selling the pills for money. Across the country, chronic pain sufferers are finding it increasingly difficult to obtain the powerful prescription painkiller, dubbed "Hillbilly Heroin" because of its burgeoning abuse as a narcotic in Appalachia.