https://en.wikipedia.org/wiki/Perfect_competition#Basic_stru...
If drug use and drug-making were both made fully legal, or comparable legal as alcohol-making and alcohol-using, then the industry would rapidly approach perfect competition for certain classes of categories (e.g., pharmaceutical recreational drugs).
Hell, even look at legal, non-recreational drugs. There can be an identical generic version. There can be an accredited medical professional standing right there saying "they're the same thing" and people will still opt for name brand.
I'm certain that if drugs were legalised, all that extra cost from being illegal would go straight in to marketing budgets and people will be buying the lsd equivalent of $300 bottles of wine or vodka that comes in creative packaging.
(Yes, brands have an influence, people buy Vertu phones, but Walmart has a lot more customers.)
It seems unlikely that other recreational drugs would be different.
Would we see the same phenomenon with generic diacetylmorphine and artisinal heroin? That would certainly be amusing...
Why do I think this? I have many friends in Colorado. No weed dealer there was upset at having more production available.