Looking at remdesivir and its synthesis I see slowness and bottlenecks everywhere. From wiki's remdesivir page.
Some of the reagents aren't going to be in high demand. I don't see "speedy" oozing from the process. And I see no mention of yields, which I suspect are low for most of the steps. And I don't see why favipiravir would necessarily have a much simpler synthesis. (Makes me appreciate all the work done to edit yeast genomes to produce this kind of thing.)
Synthesis of Remdesivir in structural formula.
Remdesivir can be synthesized in multiple steps from ribose derivatives. The figure below is one of the synthesis route of remdesivir invented by Chun and coauthors from Gilead Sciences.[29] In this method, intermediate a is firstly prepared from L-alanine and phenyl phosphorodichloridate in presence of triethylamine and dichloromethane; triple benzyl-protected ribose is oxidized by dimethyl sulfoxide with acetic anhydride and give the lactone intermediate b; pyrrolo[2,1-f][1,2,4]triazin-4-amine is brominated, and the amine group is protected by excess trimethylsilyl chloride. n-Butyllithium undergoes a halogen-lithium exchange reaction with the bromide at −78 °C (−108 °F) to yield the intermediate c. The intermediate b is then added to a solution containing intermediate c dropwise. After quenching the reaction in a weakly acidic aqueous solution, a mixture of 1: 1 anomers was obtained. It was then reacted with an excess of trimethylsilyl cyanide in dichloromethane at −78 °C (−108 °F) for 10 minutes. Trimethylsilyl triflate was added and reacts for an additional 1 hour, and the mixture was quenched in an aqueous sodium hydrogen carbonate. A nitrile intermediate was obtained. The protective group, benzyl, was then removed with boron trichloride in dichloromethane at −20 °C (−4 °F). The excess of boron trichloride was quenched in a mixture of potassium carbonate and methanol. A benzyl-free intermediate was obtained. The isomers were then separated via reversed-phase HPLC. The optically pure compound and intermediate a are reacted with trimethyl phosphate and methylimidazole to obtain a diastereomer mixture of remdesivir. In the end, optically pure remdesivir can be obtained through chiral resolution methods.