Profit motive is the most likely explanation. Total revenue for a treatment that only 15% or so of the population would need, vs everyone needing 2, 3, 4 doses of vaccine? They want to maximize domestic and international sales of vaccines before moving on.. spike MABs finally getting used, though they were available all last year. Mutations mean both will eventually be useless / need new development. The changing landscape re: variants means that a variant agnostic therapeutic like LLMab will be needed at some point.

I actually thing they passed on HGEN bc they know LLMab is the superior option.. approving one subpar treatment first might make an EUA impossible for a second, superior option.