Yes, and Zizek has also made movies. Wittgenstein never published anything but his dissertation, but left 20,000 pages of manuscripts behind. Some people are known largely thru the publication of notes taken by students. There are many difficulties.

Just figuring out how much time a person had to write seems pretty important. Einstein was at the Princeton institute for advanced studies, so he had no teaching duties. Nietzsche was sick a lot of the time. Wittgenstein spent years working as a gardener.

Number of journals in a field is also probably important. Reputation of journals may or may not be worth factoring in. And now we have blog posts to count.

Since the best you can show with this is a loose correlation, you're going to run into troubles across different fields. For example, the Intelligent Design people aren't rigorous in their methodologies and don't produce a lot of academic writing. So they don't fit your model. Maybe if you add all non-academic sources, like the propaganda they produce?