The short version
8 companies supply this market — a reasonable cushion if one runs into trouble. The generic price has fallen 64% in a year, to $0.5579 per mL — and generics that get this cheap tend to get abandoned rather than defended. Historically, drugs in this position went on to a new shortage within 90 days about 0.4% of the time — roughly 3× the typical drug (0.1%).