So, are slow writers the norm?
By that I do not mean: Do most writers write as a less than fast pace?
I meant to ask: Are most writers unintelligent?
I think the answer is no.
Based on simple observation, I would guess that writers actually have above-average intelligence.
Where successful writers probably differ the most is in formal education.
For every outstanding C.S. Lewis and Alan Jacobs (professors), there seems to be a Ryan Holiday and a Gore Vidal (both who did not complete formal university).
While above average intelligence might aid a writer, extreme intelligence might be a hindrance?
Most writers I know are broad thinkers.
If you want to mess with only technicalities, you might be a better fit in engineering or medicine.
We can have high IQs and all sorts of impressive degrees. Some of us can conjugate verbs in three languages, or understand particle physics. Maybe we went to Ivy League schools, or are members of Mensa. But being wicked smart won’t help you when you’re following a line of words on the page. In fact, being that kind of smart can turn out to be a problem. I know a few writers—intellectual, erudite people—whose work suffers for their brilliance. Though there is no such thing as too smart to be, say, a rocket scientist or a neurosurgeon, it is indeed possible to be too smart to be a writer.
-Dani Shapiro, Still Writing