The last thing a pharmaceutical company wants is for their drug to be abused by addicts and then they recieve the bad press that they do.
These drugs are addictive but need to used where addiction is not going to be a problem - a terminally ill patient who is going to die soon and just needs a couple of weeks. months or days painfree. Amphetamines are also used in this way - to give a patient more energy to maybe attend a their childs wedding before they die or increase appeitite to stop them from starving.
If you were ever to see a patient in absolute agony from a cancerous dressing change or moving them out of bed, then you would realise that these drugs are so, so necessary.
They are actually not big business really. If prescribed correctly then a patient should only need them for a couple of months, as unfortunately they will die. However, a heart drug, that a patient may take for 25 years is big business.
It makes me mad that when someone is stricken with cancer they might be denied the correct pain relieving drugs due to addicts that cannot be trusted.
However, prescribing such drugs for migraines or back pain, can only lead to problems and education and guidelines are the key to stopping this happen.