There was an FDA approved competitor. It got pulled from the market because of fears it wasn't delivering the right dosage, and the company selling the drug wasn't willing to put up with the potential liability.
There are also companies making generics for Adrenaclick, they cost ~$140.
It's not like these decisions are being made purely on a scientific basis.
In reality the FDA is too conservative due to the incentive structure: people getting hurt from a drug approved too fast are very visible. People that get hurt due to a drug being approved too slowly are not. This is the core issue.