no - there's a huge amount of research already happening, but the biggest cost in drug development occurs after you have a target. The reason funding appears low, is because the expensive parts of drug discovery are late in the process - things like the large scale trials, etc. I would not be surprised if (I have not looked it up) a significant contributor to the amount spent on research in HIV is on late stage trials, because realistically at this point the majority of new HIV drugs should actually work, and you need the large scale tests to see if the drugs work better.

I'd like to see sources please, since I don't believe that claim. The years and years of research of many teams all over the world should exceed the amount of money required for large-scale trials by orders of magnitude.

Please note that I don't speak of an individual research team but of all teams globally combined working on that goal.

I'm sure that for any given drug you'll see a pattern of later research costing more, but as a field, unless we happen to get lucky early on with figuring out the basic science (which we clearly didn't with neurodegeneration), we'll need years (or decades to centuries - emperor of all maladies is an excellent read into the amount of work and time it took to understand cancer to the level we do now) to understand what to spend money on drugs on, and we'll have to pay for all the dead ends there too.