To rephrase the question, based on a book I read (which I have been searching for today in vain), Augustine is estimated to have written about 4.5 million words.
Now, the math. 4.5 million divided by 88 (volumes) would be <52,000 words per volume. Those 88 volumes could easily be everything.
Actually there are Autustine’s known, extant writings, translated into English; there are his other known writings, if any, not yet translated; there are works we know about because others referenced them but we don’t have them now; but there are also potentially other works that could emerge from some monastery library or someplace, which we knew about or didn’t know about. Are any of his works still being located in recent years?
One reason we have so much from him is that people wrote down his sermons, and he preached a great deal. I’m tempted to lament that we don’t have preaching bishops like Augustine anymore, but then I’m no match for Augustine either.
How would we compare the total available written output by these 3 prolific people: Augustine, Thomas Aquinas, and G. K. Chesterton? I know Chesterton’s known work strangely keeps expanding, as “new” essays and poems are discovered every year in old obscure publications. You wouldn’t think that would happen in the 20th century.
I would also wonder how they compare in works
about them. My guess is that Thomas is ahead of Augustine, and Augustine far, far, far ahead of GKC.