Not as prescribed, no, but as an alternative recreational drug is less far-fetched. What surprises me more frankly is that no large corporations appear to be gearing up to enter the legal pot market (think BT developing solar power; can't hurt to diversify...).
If that were true, that legal marijuana leads to less abuse of "harder" drugs like opioids, then the drug companies should be happy about that.
They might have been able to make more money off their drugs when people abused them, but not really anymore. It's a pretty big social issue now and companies are trending pretty lightly in this area.