Sure it is. Gilead made 100 billion dollars curring Hep-C with seed research investments that were probably much less than 1 billion. So as long as this strong differential and potential for profit exists, drug companies feel competitive pressure to produce better treatments, irrespective of the fact that "milking" the pathology would yield them trillions collectively. It's effectively a "tragedy of the commons" of s…
Goldman is rightly pointing out that gene therapy cures require heavy research but don't provide long term revenue streams.
It doesn't claim that they shouldn't be pursued, or that people should be kept sick. It doesn't even say gene therapy companies offering cures are bad investments! Rather, it points out that they offer high returns over limited durations, and will have to constantly hunt new treatments and target popular diseases. All of which, I note, describes Gilead perfectly.
I think you and Goldman are both right, while the headline writer is misunderstanding the actual memo.