Milton Friedman invested decades of his time in being a public intellectual. Writing Capitalism and Freedom in 1962, newspaper columns from the 1960s, countless television interviews and public speeches, travelled the world, and of course his famous 1970s TV series Free to Choose. Friedman wrote a bestselling autobiography Two Lucky People and many other books for popular audiences.
If Democracy in Chains is to be believed, James Buchanan was far more influential in a dastardly Machiavelli way despite no work as a public intellectual, hardly any online video clips, a difficult writing style, and a dry way of public speaking. His only known public policy position would be his advocacy of ruinous inheritance taxes.
Other than that, Buchanan devoted himself to the technical aspects of public choice economics. As a teacher, I am told that he crammed all his lectures into 2-weeks to get back to his desk as quickly as possible without further interruption from students.
If only Milton had known. You can be immensely influential despite making no effort to publicise your views or participate in public debate or even be all that articulate. As Nancy MacLean herself noticed
There are a few reasons Buchanan has been overlooked. One is that the Koch cause does not advertise his work, preferring to tout the sunnier primers of Hayek, Friedman and even Ayn Rand when recruiting. Buchanan is the advanced course, as it were, for the already committed. Another is that Buchanan did not seek the limelight like Friedman, so few on the left have even heard of him. I myself learned of him only by serendipity, in a footnote about the Virginia schools fight.