We are chewing this topic over and over again. Trials are going on, it's not about beliefs, but statistical significant results.
But you pose a very good thought. The U.S. are dealing with systematic issues. If you aren't part of big pharma then the enrollment process of any drug, may it be as promising as Leronlimab, is awfully slow and / or maybe too costly to get it across the finish line. Success merely depends on the quality of the investigated drug, but on perseverance, luck and the good will of certain people.