The short version
21 companies supply this market — deep enough that no single failure threatens the supply. The generic price has fallen 42% in a year, to $494.81 per mL — and generics that get this cheap tend to get abandoned rather than defended. The brand runs $1167.90 per mL — 2.4× more. Historically, drugs in this position went on to a new shortage within 90 days about 0.2% of the time — roughly 2× the typical drug (0.1%).