1. It isn't so difficult. "Pharma" makes drugs from plants all the time. It isn't hard to imagine having strains specifically for treatment, packaged in prepackaged dosages with the right strains with different strengths. Or inhalers and things. "Pharma" also makes things like aspirin, after all. Besides, "Pharma" isn't the only one with an interest here - alcohol and tobacco companies would surely jump in to fill the niche. Not to mention that many countries have taxpayer-funded health care and have a vested interest to provide lower-cost treatments that work.

2. It depends on what is causing your migraines. I have a family member that will smoke occasionally if the migraines get bad enough. But they also have allergies, and sometimes smoking irritates them. That means that she has a small chance of the headache changing forms. One type of pain traded for another.

3. The situation is pretty horrible. I don't have them, but they run in my family. I've had to pick a person up because they got an aura while driving. I've known another that goes literally months with headaches. The pain gets bad enough that folks near "If I overdose, at least the pain stops". It can literally disable folks for hours. Cannabis doesn't always work well enough and doesn't prevent them. Most things that help with the pain still disable folks enough that they can't drive nor do their work.