The short version
Only one company currently supplies this market — there is no backup if it stumbles. The price has fallen 56% in a year, to $0.7287 per gram — and generics that get this cheap tend to get abandoned rather than defended. Put together: this is a fragile supply — if anything else goes wrong, there is very little slack to absorb it.
The numbers behind every sentence are on this page below — and the Watch button emails you when any of them move.