I was going to say armed insurrection, but on second thought that might be ethical under those circumstances.
Unethically probably the most gain could be in manufacturing fake medicine. Cheap inputs, expensive prices.
Ah, in fact, even better for repeat customers: Making real medicine and selling the hard stuff over the counter (assuming drug schedules are “regulation”).
Fair point, but without regulations your claims can be way wilder, and you don’t have to make stuff safe to ingest anymore. Overall I think quackery can become even more profitable.