[kingkawn]

This is because a broad spectrum antibiotic with low resistance is an essential public good that will likely rapidly be made generic by either legal action or international disregard for copyright law. So no major pharma companies will want to invest resources into the development of something like this, and governments are not under the gun enough to produce new abx to invest the billions needed to get it through the approval process. The compromise is to leave it sitting at this phase until some disaster creates enough public incentive to socialize the completion of its development.