I'd be afraid that they'd turn to other illegal activities like kidnapping and bribery before entertaining a legal job.
If the cartels are allowed to operate legally, I'm worried about them having committed crimes for decades and being rewarded with first moved advantage into the new market. I think that would be a slap in the face to the rule of law. I'm not worried about the consumer as typically people should be able to self medicate and experiment as you suggest.
They can't if they've commited crimes and are in search and capture, like most of the heads are. If you're a mid scale weed producer that didn't use violence, sure, you have a headstart.
If you're a meth producer that killed (suspected) competitors and snitches, you're in for a lot of problems if you want to make your business legal.
"Oh, hi. I'd like to register a new LLC, these are my papers..."
If the cartels are allowed to operate legally, I'm worried about them having committed crimes for decades and being rewarded with first moved advantage into the new market. I think that would be a slap in the face to the rule of law. I'm not worried about the consumer as typically people should be able to self medicate and experiment as you suggest.