It's why those few drugs listed sit in that same space in comparison to Gilead with their HIV treatment that grew them to where they are. Drugs with HUGE markets and no or very limited options meaning success in any will dominate very large markets. Alzheimer's market estimated at $20B pa (PBT) & TBI/Rett/FragileX in excess of $10B market pa(NEU same drug against each). If your the only solution it's pretty simple math.
Put it this way the largest selling pharmaceutical drug still remains under $10B.
