Let's say my doctor says to me "you're depressed, I'm prescribing esketamine, go to this clinic and pay them $3000". Well, I do my research and learn that really this stuff has the same antidepressants effect as ketamine. And the same number of doses of ket on the darknet markets are going to cost me a heck of a lot less.
Sure, there's the question of legality. But if I can't afford esketamine but can afford dodgy internet ket, and I'm desperate for something, anything, to help with this nagging constant psychic pain weighing down my life...
Suddenly I appreciate my Canadian single payer health care system a lot more, even with the small problems it has.