Researcher output dropping precipitously

I listened to an interview with Patrick Collison on Econtalk about an article on diminishing returns in science he wrote.

We do know that the number of working scientists has increased enormously. Right? And so I think it’s kind of a very reasonable and valid question, ‘Well, okay: For that increase,’ and again, it is vast , you know, ‘Have we gotten a proportional increase in the rate of discovery?’ Right? And like, that should not be a hard question to answer. If the number of scientists have increased by, say, 20%, you know, perhaps the kind of error bars and all this stuff are so wide that we can’t tell whether it’s a 20% increase or not. But we are not talking about, um, sort of a 20% increase in our inputs. Depending on the measure you take, it varies. What we are talking about is increases of between sort of 10 X and 100 X. And if we are investing 10 X to 100 X more, it should really not be a difficult question: Are we getting 10X to 100X more output than we were previously?

A lot of that is surely that the low hanging fruit has been picked but I guess the following is also big part of the problem:

I mean, you read the early history of sort of the great academic institutions in the US, or the biographies of many of those who made some of the most important breakthroughs. And there is a kind of free-wheeling nature to them, that does seem far less prevalent today. I was having this conversation recently with David Deutsch, the physicist–you know, some really significant work in quantum computing. Foundational work. And, you know, we were kind of reflecting on and sort of chatting about his career. And he was very firmly of the view that he could not have had the career he did, and could not have done the work that he did, had he been starting out today. Because, he didn’t fit in any neat box.