Define true, it is true that the US spends more on medical research than the rest of the world combined, and produces more drug patents than the rest of the world combined.
The US always had the best facilities, biomedical research started in the US the Rockefeller University was the first one in the world iirc.
This doesn’t explain it really what could explain it is that as the cost of developing a drug became higher more and more players dropped out of the game especially as the revenues started shrinking due to Indian generics becoming popular around the world.
https://assets1b.milkeninstitute.org/assets/Publication/Rese...
This btw went up fairly recently especially since Indian generics became accepted world wide in the late 90’s and early 2000’s.
The US used to produce 20-30% of the world’s drug patents now its peaking at 60%.