Because 'works' in a medical context is a boolean that encompasses everything from 'order of magnitude lower chances of death' (effective vaccines) to '1% relat

Because 'works' in a medical context is a boolean that encompasses everything from 'order of magnitude lower chances of death' (effective vaccines) to '1% relative reduction in death' (off-label use of some random drug not intended to target improvement in COVID recovery), so the focus has naturally been on finding treatments with high effect sizes and distributing them as quickly as possible. Not to mention the herd immunity element to vaccines.