Without intimate familiarity in the field it's really hard to figure out cause and effect in something so complicated. It's been noted that it's become much ha

Without intimate familiarity in the field it's really hard to figure out cause and effect in something so complicated. It's been noted that it's become much harder to find new drugs. Conventional explanations are that we're pretty good at this by now, and all the low hanging fruit has been picked (there's also fields like antibiotics where few are trying for unrelated issues). More rigor in studies could be a cause, and/or there may be fewer successes because its become that much harder, and more iffy attempts are being made.