In The Annotated Gulliver's Travels, Isaac Asimov speaks to this passage.
"This is one of the best-known bits of scientific satire in this section of the book, and yet Swift, without knowing it, had something there.
As given here it sounds very much like that old bromide that if a thousand monkeys are set to tapping the keys of a typewriter at random, they owuld, given enough time, turn out all the books in the British Museum (or in the Library of Congress).
The catch is, of course, "given enough time." The entire lifetime of the universe would probably not be enough for a significant chance of turning out a page of significant prose.
However, that bit about making the strictest computation of the various components of the language puts Swift on the right track (and is another example of his astonishing, if accidental, prescience).
We no longer have to have long rows and tiers of blocks to be turned by hand, as shown in the illustration. We have computers now which can work their way through random combinations millions of times faster than human beings can.
Furthermore, if the complete works of certain writers are analyzed, and if, instead of counting the frequency of individual words, we work out the frequency of two word, three word, and four
Isaac Asimov (January 2, 1920 -April 6, 1992) annotated Gulliver's Travels in 1980. He completed his comment on this passage with
"While the computerized production of books is not yet on the horizon, it is by no means totally inconceivable."
We may not have computers that totally write the books, but we now have computerized books. They are called E-books. I think Mr. Asimov would have approved.