Approximately 3,000 scientific articles are published per day – roughly one every 10 seconds of a working day. We can now expect that these papers will, each year, cite around five million previous publications. And the rate of production of scientific papers is quadrupling every generation. (All these estimates are based on data from the Institute for Scientific Information.) The percentage of human knowledge that one scientist can absorb is rapidly heading towards zero. This side of a new Dark Age, there will never be another Da Vinci.
Whenever Tom Coburn proposes cutting NSF funding and everyone squeals something like this comes to my mind. And, like Harford, I support public (and private!) research funding, but we need to be realistic about what exactly the return to that investment is. The old romantic ideal of scholar-polymath is over, and that was inevitable. Moreover, it's a good thing; it means that knowledge has progressed massively, to the point where no single person can absorb it all. We all have to fill our niches, and then try to make our niche-work known so it has some relevance for the outside world. So let's just recognize that we're working on the margins and try to do the best with that that we can.
Meanwhile human progress marches on.