Well therein lies the rub. There has been a lot of study, but all very small and scattered around the world by clinicians. There has been a lack of uniformity in the studies. The trials that show lack of statistical meaningful results often don't use the same protocols as the studies that seem to show benefits. Nearly all of these potential treatments (and I stress potential, recognizing few if any were large randomized studies) need to be given as early in the disease cycle as possible - e.g. upon positive test and/or onset of first symptoms even before PCR test confirms.
So again my point is, no interest in actually enrolling a 10,000-30,000 person study for anything that would be fast and cheap to produce to help those who are actively infected. This thing is rampaging throughout the world and little hope to produce enough vaccines in any meaningful quantities to stop it.
Large clinical trials like what you’re describing are very expensive to run (averaging about $50 million each) and fail about 90% of the time. Unless the government is handing out tons of free money to finance those trials, they’re unlikely to be run.
Now, in an era where government is throwing mountains of money at anything and everything (except you and me), could they have spared some cash to run such trials? Sure. And I wouldn’t be against that. But I don’t expect drug companies to volunteer to pick up the tab to try random drugs and protocols in the hopes that something, somewhere pans out.
Unfortunately, large scale trials are expensive. There were a couple HCQ trials, including the University of Minnesota HCQ trial that was funded by Novartis and others, but the trials showed no actual benefit. There are now a couple of ivermectin studies starting. Unfortunately, the internet hype never seems to translate to reality, as several Freeper MDs with hands on clinical COVID experience have stated. And it’s not just cheap generics that this applies to. Several super expensive drugs, like Remdesivir, have also been hyped, only to show disappointing results in the real world.