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.